PeepSo Email Digest Addon GPL Overview:
Bring users back with newsletter-style emails. It’s intended to bring users back to the community and to build engagement through enticing content delivered by email. Because it only sends those emails to users who haven’t logged in during a period specified by the admin, it won’t bother active members; it will only show inactive members what they’ve been missing.
The plugin automatically sends those members a summary of the most engaging posts in the community, the posts with the most likes and largest number of comments. Admins can define the duration of the users’ inactivity and set the number of posts to include in the digest.