Segmentation
Setting a condition on your list to isolate a targeted subset of subscribers, and knowing how many people that condition currently represents.
Why it matters
A segment answers a question you ask yourself before writing: how many people opened last month, how many came from the March trade show, how many are still there. Writing blindly is the number-one cause of unsubscribes.
A segment is a question asked of the list, not a copy of it: 'subscribed within the last thirty days', 'tagged March trade show'. Nothing is duplicated — the question re-runs on its own every time you open it, and someone who subscribes tomorrow enters it without anyone doing a thing.
Four conditions can be combined with AND: status, a tag, an open or click within the last N days, a recent signup. And the counter shows two numbers — how many people the rule matches, and how many of those are still subscribed.
In Mailcheer, a campaign can target a segment. The segment is evaluated when the campaign goes out, not when it is written: the campaign reaches the people who match at send time, minus unsubscribes and the suppression list. If the targeted segment has since been deleted, nothing goes out until a new audience is chosen.