Thread:Sannse/@comment-5393530-20121014224702/@comment-8-20121016175001

It's automatic (although it's possible to turn it off). They system sends it to each person who edits, and signs it (usually) with the name of a recently active admin. If you use message wall on your wiki, then the admin who signed will be notified if the person respond - a good way of starting to bring them in to your community!