A segment is a saved group of contacts. Create them under Email → Segments.
Rules
- Tags: contacts with any of the tags you pick, or all of them.
- Source: how contacts joined, such as a form, the store, an import, or added by hand.
A segment updates as contacts change, so someone who gets a matching tag later is included in the next send. Campaigns only ever go to subscribed contacts, whatever the segment says.
Segments can't filter by opens, clicks, or dates.