Requested feature overview description.
Some need positive feedback and sometimes it's good to give that when you see someone doing something positive.

Have "Thanks!" (or some furry variation which all the cool furs use) button next to tag, note and wiki edit history. This would then show up green bar on top of page saying "<user> thanked you for your edit in <place> <change>" which user can easily dismiss. This way they get the feedback, without needing to open their inbox.

Reduce the amount of thanks user can give into something really low (1/week) so that system cannot be abused, users who actually do lots of things won't get spammed and keeps positivity of getting thanks high.

E: partially stolen idea from this https://www.mediawiki.org/wiki/Extension:Thanks[/i]Why would it be useful?
Right now sites system is based on that only administration can give "green bars", which is not only rare, but sometimes someone doing good small things can be left unnoticed - because how much easier it is to notice negative behavior going on. This would give regular users way to quickly thank someone without needing to get annoying with dmails. What part(s) of the site page(s) are affected?
Tag, note and wiki edit history, notification system.