I've thought about trying to start some movement, not sure how to spread the word, that each open source project on github should make a "thank you" issue and pin it as a place for people to say thank you.

AFAIK It's frowned on to say thank you in issues but it also sucks to have projects with 100s or 1000s of stars/forks and not a single thank you what so ever.

Medium has the "claps" but I think it would be even nicer when you clicked it it prompted for a comment.