# Tags vs segments: labels you set and audiences you define

A tag is a label you put on a subscriber; a segment is a rule that works out who matches. When to use each, and how tags and segments work in Mimeo.

**Definition:** A tag is a label you put on a person, such as customer or webinar-attended. A segment is a saved rule, such as "bought in the last 90 days", that works out who matches each time it is used.

## How it works

A **tag** is set by something: you, an import, a signup form, an automation. It stays until something removes it. Tags record facts nothing else captures, such as "came from the spring webinar".

A **segment** is a question about your list. It can ask about anything known about a person: fields, tags, purchases, opens, clicks, events. Nobody adds people to it. They match or they don't, and they move in or out as soon as their data changes.

The two work together. A tag can be one rule inside a segment:

- Tag: `webinar-attended`, added when the webinar tool reports attendance.
- Segment: has the tag `webinar-attended`, hasn't bought `pro-plan`, isn't suppressed.
- Broadcast: the replay offer, sent to that segment.

## Why it matters

- **Tags go stale.** A tag like `engaged` is true the day you add it and wrong a month later. A segment on recent clicks stays right.
- **Too many tags become clutter.** Spellings drift and nobody remembers which one a flow uses.
- **Segments answer at send time.** Someone who bought this morning drops out of tonight's "hasn't bought" broadcast without anyone touching the list.

## How Mimeo handles it

Mimeo has both. A [tag](https://mimeohq.com/docs/usage/people#tags) is created the first time anything adds it to a person: you, a flow step, an event or an import. Each change fires `tag_added` or `tag_removed`, so a tag can start a flow. An email can show or hide a block by tag with [`person.tags`](https://mimeohq.com/docs/usage/emails#tag-conditionals). **People → Tags** lists every tag with its count, and renaming one updates every flow, segment, guard, email and template that names it.

A [segment](https://mimeohq.com/docs/usage/segments) is a live rule over email address, fields, tags, suppression, subscribe date, money, engagement, events and run history. Membership is worked out when a broadcast sends or a flow branch asks, never frozen. A segment can include another segment, and one marked "should be empty" becomes a watchdog that alerts you when anyone appears in it. Your agent can build and check segments through the API and MCP. See [Mimeo terms](https://mimeohq.com/docs/glossary#working-in-mimeo) for tags and segments in Mimeo's own words.

## Sources

1. [People](https://mimeohq.com/docs/usage/people), checked 2026-11-09
2. [Segments](https://mimeohq.com/docs/usage/segments), checked 2026-11-09

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This is the Markdown copy of https://mimeohq.com/glossary/tags-vs-segments.