Social tools/Echo

Social tools extensions have been progressing to eventually support Echo notifications for different events. Currently, only SocialProfile supports these so far.

SocialProfile
SocailProfile's initial echo support was originally added by Ikasty on a fork, which can be seen at https://git.io/v1W5n. It was partially rewritten, expanded on and cleaned up by, and merged by. 
 * SystemGifts

WikiForum
WikiForum doesn't have notifications, but it was worked on by in commit  a few months after ticket #355 at brickimedia/brickimedia on GitHub was created. It has since then been abandoned.