Segments

Selecting contacts by condition, and why the size needs recounting.

A segment is a saved set of conditions over the contact base — “everyone who did X”, rather than a list of names. It is the precise way to choose a broadcast audience.

The list

Each segment shows its name, how many conditions it is built from, its size, and when that size was last counted.

Three actions sit on every row: Recount, Edit, Delete.

Size is a snapshot, not a live number

This is the one thing about segments worth understanding, and the Counted column is the clue.

A segment’s size is calculated when you ask for it and stored. It does not update itself as contacts arrive, change, or leave. A segment counted a month ago shows what it matched a month ago.

Recount re-evaluates the conditions against the contact base as it stands now.

Recount before using a segment for a broadcast. Sending against a stale count is not dangerous in itself — the conditions are re-evaluated when the send runs, so the right people are reached either way — but you will be deciding whether to send based on a number that no longer describes anything.

Segments and groups

Both narrow the contact base, and they are not interchangeable:

Segment	A condition. Membership is derived, and changes as contacts do.
Group	A list. Membership is assigned, and changes when someone changes it.

Use a segment for “everyone who bought in the last month” — nobody should have to maintain that. Use a group for “beta testers” — that is a decision, not a property.

Empty segments

A size of zero means the conditions currently match nobody. That is a legitimate state — a segment for “abandoned cart in the last hour” is empty most of the time — but if you did not expect it, the conditions are usually narrower than intended rather than the contact base being emptier than expected.