Understanding the Keywords Field in Email Headers

Ever notice those keywords under each message in your inbox view? The Keywords field is an unsung hero that can transform the way you organize, search, and filter emails when leveraged properly.
While this customizable header is not part of the standard, services like Mutant Mail make it a game changer for productivity at scale.

Let’s dig into everything about the Keywords header so you can take back dozens of hours from endless scrolling and searching.

What is the Keywords Field in Email?

The Keywords field in email refers to a custom header that some email clients and services allow senders to add when composing a message. This field can be used to assign relevant keywords or tags to emails.
Although Keywords is not standardized in protocols like RFC 822 that define email headers, it offers useful functionality for organization and searching. Let’s break down exactly what the Keywords header is all about.

Definition and Overview of the Keywords Header

In simple terms, the Keywords field enables attaching a string of keywords or tags to an email, separate by commas or other delimiters. For example:

Keywords: sales,prospecting,outreach

Or:

Keywords: weekly-newsletter,campaigns,promotions

These keywords help to categorize the email for better identification when searching or reviewing messages later.

Unlike default headers like Subject which only take a single text value, the Keywords field is designed to accept multiple keywords. Delimiters like commas, semicolons, or spaces allow including distinct tags as needed.

Some key facts about the Keywords header:

  • It can contain any relevant words that describe or identify the email. Common choices include project names, topics, categories, recipient groups, or campaign names.
  • The field is added when composing the email in the email client. The keywords persist when the message is sent and received, allowing enhanced searchability.
  • There is no restriction on the number of keywords that can be added. However, best practice is to only include tightly relevant keywords to keep things focused.
  • The format and parsing of keywords depends on the email service or client used. Some may treat multiple keywords as a single string, while others recognize delimited values.
  • Keywords allows adding metadata not easily captured in other headers like Subject. This supplemental information can make managing and digging into emails much easier.

Use Cases and Benefits of Email Keywords

There are a variety of potential use cases where adding an email Keywords header can provide value:

  • Searching and filtering – Keywords enables quickly searching for emails based on topic, project, recipients, campaign name, or other criteria. For example, filtering to all emails with the “newsletter” keyword.
  • Email rules and automation – On the server-side, email services can implement rules and filters based on Keywords values to auto-file, forward, or notify on messages.
  • Email productivity – Teams can standardize a set of common Keywords values to tag client emails, project tasks, newsletters, and other frequently communicated topics for fast retrieval.
  • Email analytics – Marketing and sales teams can track open, click, and reply rates on campaigns by associating a unique Keywords value with emails sent.
  • Mail list management – Mailing list tools like LISTSERV allow controlling whether Keyword headers are passed through on list emails based on admin preferences.

Overall, the main benefits provided by keywords include simplified email organization, faster searching and filtering, and enabling email rules and automation based on message metadata.

How Keywords Help Organize and Search Emails

At its core, the primary aim of the Keywords header is to make finding and working with emails easier and more efficient. Here are some of the ways it helps with organization and discoverability:

  • Grouping – You can logically group related emails under a common Keyword value, like “newsletter” or “client-prospecting”. This makes retrieval faster.
  • Sorting and filtering – Sorting by Keywords or filtering emails that match specific Keyword values allows drilling into relevant messages quickly.
  • Search precision – Searching for keywords finds emails that may not match in the Subject but have the relevant Keywords applied.
  • Quick identification – At a glance, you can identify what an email is about based on the Keywords visible in message lists.
  • Virtual folders – Keywords enables creating virtual folders to view emails with specific keywords applied on-the-fly.
  • Email rules – Server-side rules can leverage Keywords to auto-file messages to appropriate folders based on the keywords.
  • Metadata-powered productivity – Features like Unified Inbox in Mutant Mail harness Keywords metadata for features like one-click filtering and search.

With the right processes, Keywords can transform unwieldy inboxes into well-organized systems for fast email processing. The time saved really adds up for busy professionals.

Keywords provides a flexible way to add supplemental metadata that complements standard headers like Subject. This metadata makes emails much easier to visually identify, search, group, filter, and organize automatically. Any email user that needs to efficiently manage high volumes of messages can benefit from a streamlined keywords approach.

Adding a Custom Keywords Field in Popular Email Clients

While the Keywords header is not natively supported in most popular email services, there are ways to enable adding this useful metadata in some clients. Let’s look at options for adding custom Keywords in Microsoft Outlook, Gmail, and leveraging it effectively with Mutant Mail.

Enabling a Keywords Field in Microsoft Outlook

Outlook does not have an out-of-the-box Keywords field that can be added when composing new messages. However, there are a couple of options to add this functionality:

Custom add-ins – Third-party add-ins are available that extend Outlook with a Keywords field for tagging messages. Popular options include Alto Email Management and Email Management Toolkit. These integrate seamlessly with Outlook on the desktop.

Macros – Users can create Visual Basic macros that add a Keywords text box in the message window. The macro can pre-populate it with values, validate entries, and process the keywords when sending. This does require some coding expertise.

Category tags – Outlook’s native Categories feature allows adding predefined tags to messages that can be used similarly to Keywords. However, Categories are fixed values rather than freeform strings.

Server-side rules – An Exchange admin can set up server-side rules that extract keywords from the message body and apply them as metadata for searching in Outlook.

Save as draft – Manually adding Keywords in the message body and saving emails as drafts preserves them as searchable properties when messages are sent for real.

So in summary, while not straightforward, it is possible to leverage keywords in Outlook for power users who are willing to explore add-ins, macros, or unconventional approaches like using the body as temporary storage.

Using Categories as an Alternative in Outlook

The Categories feature in Outlook provides an alternative way to tag messages for easier organization. Here’s an overview:

  • Predefined color categories can be enabled in Outlook and applied to messages while composing or after sending or receiving.
  • Categories are fixed values unlike freeform Keywords, but serve a similar grouping and filtering purpose.
  • Emails can be sorted, filtered, or searched based on the assigned Categories to retrieve related messages quickly.
  • A rule can be created to auto-assign categories based on sender, subject keywords, or other criteria.
  • Categories are a native Outlook feature available out-of-the-box, and may fit basic use cases needing some email organization.
  • For advanced uses, Categories lack the flexibility of customizable values that Keywords provide.

Overall, Categories are a viable alternative for basic email tagging needs for Outlook users not needing freeform keywords.

Adding Custom Headers in Gmail

Gmail provides an option for adding custom headers to outgoing emails, including Keywords. Here are steps to enable this:

  • Open Gmail settings and go to the Accounts and Import tab.
  • Under “Send mail as”, click on the “Send from Alias” option for your address.
  • Check the box for “Custom From: header”.
  • Save changes.

Now when composing a new message, an option to edit custom headers will appear under the From field.

  • Click “Edit headers” to add a Keywords field and values, like:

Keywords: outreach,prospecting

  • The Keywords will be persisted when the email is received by recipients.
  • Headers can also be added with Gmail’s SMTP relay by inserting them in the message body as “Keywords: value” and flagging it to be excluded from the body.

This approach allows Gmail users to incorporate Keywords in their email workflow. The only downside is having to edit headers for each message instead of a native composition field.

Leveraging Keywords with Mutant Mail’s Unified Inbox

Mutant Mail provides a Keywords header field when composing new emails under its Custom Headers feature.

More importantly, Mutant Mail is designed to leverage keywords and other email metadata for productivity and organization. Ways this is accomplished:

  • Unified Inbox automatically displays Keywords values, enabling one-click filtering of all messages by a keyword.
  • Quick Search allows searching across all managed inboxes for keywords in emails.
  • Messages can be tagged with keywords during review and when sending.
  • Rules based on keywords can be set up for automated email forwarding, notifications, and more.

By centralizing emails from multiple accounts into one unified inbox, Mutant Mail empowers users to harness keywords for simplified email management at scale. The metadata can be used consistently across hundreds of addresses.

For teams, shared keyword conventions ensure a consistent organization system. Collaboration is enhanced when everyone leverages keywords cohesively.

For sales teams, Mystrika enables tracking cold email campaign performance by keyword values associated with each outgoing message. This provides data-driven insight for improving outreach.

The bottom line is that Mutant Mail and Mystrika are designed to make excellent use of the Keywords header for productivity, unlike more basic email providers.

The Keywords Property in Microsoft Exchange Server

In Microsoft Exchange Server, the Keywords property provides server-side access to the values set in the Keywords email header. The property can be used for retrieving, managing, and automatically processing keywords applied to messages.

Mapping Keywords to the RFC 822 Header

The Keywords property in Exchange’s API directly corresponds to the Keywords header field defined in the RFC 822 email standard.

When an email arrives with a Keywords header value, Exchange parses it and makes the keywords available in the Keywords property for that message.

Some key points about this mapping:

  • The Keywords property is a string containing the comma or semicolon-separated keywords sent in the header.
  • If no Keywords header is present, the property will be empty or null in Exchange.
  • Any manipulation of keywords through Exchange results in updates to the Keywords header itself.
  • The values are stored as ASCII text, with any Unicode or non-ASCII encodings translated appropriately.
  • Keywords persists as metadata attached to messages, independent of headers in the message itself.

So in essence, the Keywords property directly mirrors the Keywords header but makes the value accessible server-side for Exchange functionality.

Retrieving and Managing Keywords with Exchange Web Services

Exchange administrators and developers can work with the Keywords property through Exchange Web Services (EWS). Some examples:

  • The GetItem EWS call returns a Message object that contains the Keywords property if present.
  • EWS calls like UpdateItem can be used to add, modify or delete the Keywords value.
  • Filters and searches can be constructed to retrieve messages with specific keywords via EWS.
  • Keywords can be added from within Exchange rules and scripts by manipulating the property.

The Keywords property provides EWS access for managing this metadata at scale across many messages in an Exchange deployment.

For end users, the integration means they can apply keywords easily through Outlook or other integrated mail clients. Admins have access to those same keywords for server-side processing via EWS.

Setting Up Server-Side Rules Based on Keywords

Exchange administrators can create server-side rules that leverage the Keywords property for automated message handling. Some examples:

  • Forwarding or CC’ing messages with certain keywords to distribution lists or individuals for notification.
  • Flagging messages with priority keywords for follow-up.
  • Routing emails to different public folders based on keyword values.
  • Triggering alerts or other actions via Exchange’s transport rules when specific keywords are detected.
  • Restricting delivery of messages with inappropriate keywords applied.
  • Automatically appending keyword values based on sender, subject, or body content.

Since keywords are persistent metadata, rules have reliable access to implement automated logic around them. This can save teams time on manual message handling and organization.

For instance, appending a “Customer” keyword to all emails from a CRM system allows easy filtering of customer communications vs internal ones down the line.

The possibilities are extensive with a thoughtful approach to keywords and Exchange rules for automation.

Using Keywords in Mailing Lists and Newsgroups

Mailing list servers and Usenet newsgroups also leverage the Keywords header in different ways. Understanding keywords handling for lists and newsgroups enables better email management.

Controlling Keywords Distribution in LISTSERV

The LISTSERV mailing list manager allows list owners to control whether the Keywords header is passed through or not in emails sent to the list.

This capability is defined by the “Keywords” keyword in the list header which accepts values:

  • Keywords= Yes – Keywords headers ARE allowed to be distributed through the list. This is the default.
  • Keywords= No – The Keywords header is stripped from messages posted to the list.
  • Keywords= List Owner – Only allows the list owner to post messages with the Keywords header intact. All others have it stripped.

So for public discussion lists, the owner may want to block keywords to avoid clutter. But for managed project lists, workflow may benefit from allowing keywords in emails between members.

LISTSERV provides granular control based on the needs of the mailing list. Some key points on its treatment of keywords:

  • Applies independently of other headers – Keyword stripping does not affect other headers.
  • Stripped keywords don’t disappear – The original message retains its Keywords header stored in the LIST archive.
  • Yes is default – List owners must actively turn off keywords distribution if not wanted.
  • Changes affect future messages – Updating the “Keywords” list keyword only impacts new posts, not existing archives.

Overall, LISTSERV gives list owners flexible options based on whether they want to leverage keywords or not.

Searching with Keywords in Newsgroup Headers

Like email, Usenet newsgroup messages contain header fields that can be searched, including Keywords.

Newsgroup clients allow searching headers for relevant keywords to find discussions easier. Some examples:

  • Google Groups provides advanced search with “haswords: keyword” to find posts with a matching Keywords header.
  • Thunderbird’s advanced search supports “keywords:linux” to return messages tagged as relevant to Linux in their Keywords header.
  • Trilio allows live header search for keywords to drill down on discussions by content tags.

In many newsgroups, contributors voluntarily add Keywords to tag the content of their posts. This creates a discoverable index of topics and conversations.

Of course, Keywords search depends on participants taking the time to tag thoughtfully. But where they do, it becomes a valuable organization system.

Tagging Emails for Simple List Management

Mailing list owners can request subscribers tag messages with Keywords to simplify list administration and searching.

Some common examples:

  • Requesting the inclusion of a “[OFFTOPIC]” keyword in the header of any non-list related emails.
  • Instructing users to apply a keyword categorizing the type of message like “[BUG]”, “[FEATURE REQUEST]”, “[QUESTION]”, etc.
  • Standard keywords for common message types like announcements, meeting notes, newsletters, etc.
  • Unique keywords for identifying messages related to particular projects or clients.

This gives list owners and subscribers alike an easy way to filter, categorize, and search the list archive by keywords.

The tagging conventions simply need to be clearly defined and communicated to the list to be effective. Compliance improves when participants understand the benefits of organizing with keywords.

Best Practices for Email Keywords

To maximize the effectiveness of the Keywords header, there are some best practices to keep in mind for choosing keywords, standardizing them across your team, tracking performance, and avoiding pitfalls.

Choosing Relevant, Specific Keywords

Aim to choose keywords thoughtfully and deliberately for each email vs just adding generic tags. Some tips:

  • Use fluent phrases that clearly describe the topic or purpose of the message rather than cryptic abbreviations. For example, “Q4 Financial Report” rather than “Q4FR”.
  • Add enough keywords to narrow down the specifics but avoid diluting the value with redundant or overlapping keywords that split hairs. 4-5 good keywords per email is ideal in most cases.
  • Reuse common keywords consistently for related messages rather than creating new variations like plurals each time.
  • Prefix keywords for emails related to a specific client or project name to group them together. For example, “Acme-Meeting Minutes” for all Acme Corp communications.
  • Use keywords conversations can be filtered by rather than broad categories, for example “Sales Prospecting” rather than just “Sales”.
  • Consider how you will want to search and filter emails later when choosing keywords – aim for maximum relevance and segmentation.

Pro tip: Maintain a controlled list of conventioned keywords and standard email tags relevant to your workflows rather than freeform values to keep your system consistent.

Standardizing Keywords Across an Organization

To enable organization-wide collaboration and consistency with keywords, establish conventions that are shared across teams and departments.

Some ideas:

  • Maintain a documented mandatory controlled vocabulary of approved keywords that everyone sticks to.
  • Make reuse and consistency an expectation rather than reinventing keywords for the same purpose.
  • Enforce compliance to conventions through training and auditing until it becomes habit.
  • Publish a knowledge base article explaining the conventions and purpose of keywords to align usage.
  • Develop email and keyword templates standardized teams can simply reuse.
  • Discourage freeform keywords instead promoting reuse of existing values.

Adopting an organizational standard prevents fragmentation into a mess of user-specific keywords making collaboration impossible. Aligning on conventions improves coordination and consistency.

Tracking Email Performance by Keyword

Services like Mutant Mail allow tracking open, clickthrough, and reply rates for emails grouped by keywords.

This enables understanding the effectiveness of specific messaging and outreach approaches based on keyword metadata.

Some ways to leverage email keywords for tracking:

  • Uniquely tag each cold email campaign, promotion, or newsletter with campaign-specific keywords to segment performance.
  • A/B test email subject lines and content optimized for different keywords.
  • Analyze the types of emails generating the most opens or engagement based on keyword trends.
  • Track how reply rates differ when contacting prospects about specific products, services, or offers using distinct keywords.
  • Use keywords as part of data-driven outreach optimization based on past results.

The ability to filter performance metrics by keyword provides actionable insight for improving email effectiveness. This can really move the needle for marketing and sales teams.

Avoiding Overusing Keywords

While keywords are useful, take care not to go overboard. Here are some pitfalls to avoid:

  • Don’t include so many keywords that it becomes difficult to parse what the email is really about at a glance. 4-8 keywords max is ideal for most cases.
  • Avoid redundant keywords that differ only slightly like plurals of the same root keyword.
  • Don’t keyword stuff by adding keywords not tightly relevant to the message just for the sake of it. Keep keywords focused.
  • Don’t force keywords where they aren’t useful just out of habit or misunderstanding their purpose. Use judiciously only where beneficial.
  • Avoid inconsistent keywords that fragment your taxonomy making organization and collaboration suffer.

The purpose of keywords is to provide supplemental metadata that enhances identification and retrieval. Like any tool, it can be misused in ways that reduce effectiveness when taken to extremes. But with some common sense, keywords can add significant value.

In summary, be selective with keywords, keep numbers reasonable, reuse consistently, and standardize organizationally to maximize the utility of this approach for streamlining email management and analytics.

Email Organization and Productivity with Keywords

When leveraged effectively, the Keywords header can transform inefficient email workflows into streamlined systems optimized for productivity and organization.

Streamlining Search and Retrieval of Emails

Keywords supercharge search and retrieval of emails in several ways:

  • Enhanced filtering – Retrieve emails matching specific keywords or groups of keywords easily by filtering on Keywords values.
  • Boolean search – Search for emails using Boolean logic across Keywords, Subject, Sender, etc. For example, “Keywords: news AND Subject: quarterly”.
  • Virtual folders – View all messages tagged with a certain keyword dynamically using virtual folders rather than static mailboxes.
  • Conversation threading – Group related back-and-forth emails in conversation threads by tagging all with a common keyword.
  • Quick searches – Save complex search queries with keywords to instantly pull up relevant message groups.
  • Unified Inbox – Services like Mutant Mail enable one-click filtering by keyword across hundreds of addresses in a unified inbox.

Overall, keywords supercharge search precision, filtering, and email grouping for fast message retrieval, reducing repetitive searching and scrolling.

Automating Email Management with Keywords-Based Rules

Server-side rules that leverage Keywords values can implement powerful message automation. Some ideas:

  • Auto-tag incoming messages from mailing lists, newsletters, users etc based on sender.
  • Forward notification emails with certain priority keywords to your cell phone for urgent review.
  • Move emails with “[OFFTOPIC]” keyword automatically to an Archive folder to declutter the inbox.
  • Flag messages from executives when they include a “[URGENT]” keyword for priority follow-up.
  • Automatically BCC emails containing competitor keywords to a Sales alias for competitive monitoring.
  • Append a case number keyword when messages arrive from your CRM system for easy case management.

Setting up rules and filters to run actions based on keywords eliminates tedious manual processing. And keywords allow very precise rules since they represent granular metadata vs just Subjects.

Integrating Keywords into Your Email Workflow

To fully benefit from keywords, integrate their use into your regular email processes:

Like any tool, the productivity gains require workflows to evolve around leveraging keywords. But once habits form, it can speed up email processing significantly. The time investment upfront pays off exponentially.

Key Takeaways on the Keywords Header Field

  • The Keywords field allows adding custom tags or keywords to email messages for easier organization and identification.
  • While not standardized, some email clients like Outlook and Gmail allow enabling custom fields like Keywords when composing emails.
  • Services like Mutant Mail fully support Keywords headers for features like rules, tracking, and unified inbox management.
  • Keywords can be controlled in mailing lists to determine if they are passed through or not in list emails.
  • In Microsoft Exchange, the Keywords property maps directly to the Keywords header for server-side management.
  • For productivity, aim to standardize keyword conventions across teams and integrate their use in workflows.
  • Tracking engagement and metrics by keyword provides insight into optimal messaging and campaigns.
  • Avoid keyword stuffing or inconsistent overuse – be selective with keywords for maximum utility.
  • Overall, the Keywords header enables easier organization, searching, automation and analytics when used intentionally.

Here are some frequently asked questions about the Keywords email header field:

Frequently Asked Questions

What are some best practices for using keywords?
Some best practices include:

  • Be selective – Only use tightly relevant keywords, 4-8 per email max. Avoid diluting value with redundant keywords.
  • Be consistent – Reuse keywords consistently rather than reinventing variations. Standardize keywords across your team.
  • Be specific – Use keywords that precisely describe the email content rather than generic tags.
  • Be intentional – Add keywords deliberately based on how you will want to search and filter emails later.

Where does the Keywords header appear in the email?

The Keywords header field appears in the message header, along with other metadata like Subject, To, From etc. It won’t be visible in the body content of the email.

Can I use keywords in Gmail?

Yes, Gmail allows adding non-standard header fields like Keywords by editing custom headers. Just enable custom headers under Settings, compose your message, and click “Edit headers” to add Keywords.

How do I add keywords in Outlook?

Outlook doesn’t have native support, but you can use add-ins like Alto to add a Keywords field. Alternatively, you can apply Categories for tagging, or use rules to extract keywords from the body into metadata.

What are some examples of useful keywords?

Examples include project names, client names, campaign names, product names, meeting types, status tags like [URGENT], and topic keywords like [SALES], [PROSPECTING], etc.

How many keywords should I use per email?

Around 4-8 relevant keywords per message is ideal. Avoid adding too many redundant or barely relevant keywords as that dilutes the value. Be selective and intentional with keywords.