The Discourse "Activity Summary" (formerly known as the "digest") is an email sent out to any members of your forum who haven't visited in a while. The contents of the summary is a list of the most popular posts & topics created over the past week.
By default this mail is sent out once every week, but users may go to their settings and choose between:
- Every three days
- Every two weeks
- Opt out
Users who have not been active on the forum for more than 365 days will stop receiving these emails.