"Welcome back" emails should be sent to users on renewed account activity who have been inactive for longer than X months with more than Y edits or advanced permissions. X and Y should be server-side variables, with possibly X configurable by the user.
The benefits of this proposal include likely improved established editor retention and detection of account cracking.
Discussion on en.wp: [[Wikipedia:Village pump (proposals)/Account security#Notify users after renewed activity]]; suggests Y ~ 1000 initially.
Version: unspecified
Severity: enhancement