“Clients tagged wholesale who've opted in and bought in the last 90 days.” A segment saves an audience like that once, so you can aim a campaign at the right people without rebuilding the filter each time.
Build an audience from three axes
On the Segments tab of Campaigns, combine conditions across three axes:
- Tags — has, or doesn't have, a tag you've applied to contacts.
- Consent — a contact's opt-in state for the channel (opted in, opted out, and so on).
- Activity — has or hasn't done something, or done it within / not within a number of days.
Save the combination with a name and reuse it whenever you launch.
A segment selects — it doesn't send
This is the important part. A segment only chooses who's in the audience. It does not decide who actually gets a message — that call is made per contact, one at a time, by the same send checkpoint every campaign and sequence goes through. So if a contact who hasn't consented happens to fall inside a segment, they are blocked at send, not emailed. Putting someone in a segment can never talk past their consent, quiet hours or a suppression.
A broken filter sends to nobody
If a saved segment's filter can't be read, it resolves to an empty audience — it fails closed. A segment will never quietly fall back to “everyone”, so a mistake shrinks your reach, it never blasts your whole list.
Access & control
Segments are part of the email & sequences module. Owners and assistants create and edit them; every send they feed is still logged with its outcome — sent, queued, or blocked with the reason — exactly as it is for any campaign.
Related: Email, campaigns and consent, Email sequences.