I'd like to make a suggestion of a plugin I use on Poison. It's called thankyou/like
I like this plugin because you can thank users for posts casually wheres rep is more rare than thanking. Plus it's public so you can see who is liking/thanking you for your posts
Added a poll as i wasn't so sure about this plugin as it stops people posting if they can just click thanks in my opinion . But we will see ;)
Well I use it on Poison and it seems as though it doesn't effect posting. You can easily just hit the thank you button then post "Great work on the code" or something like that. That's what I usually do.
I feel as the like system is good for telling somebody that you liked their content and you're a fan of it and they should continue. That's just my 2 cents though.