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 boughtpro-plan, isn't suppressed. - Broadcast: the replay offer, sent to that segment.
Why it matters
- Tags go stale. A tag like
engagedis 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 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. People → Tags lists every tag with its count, and renaming one updates every flow, segment, guard, email and template that names it.
A segment 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 for tags and segments in Mimeo's own words.