This is a good idea, I have seen a similar suggestion sometime ago. It's a good tool when you are quoted and you have nothing to reply again, but you want to show the person you have seen his message to you. So, just a thanks button, to show some respect and attention back. Or of course, when you like someone's post.
Man,why would you want to do that to the strangers ? lol You sound like a real attention seeker.
I just don't think when a post receives a "thanks" it must become highlighted or something like this. The "thanks" feature shouldn't affect this way. That was one of the reasons why many people didn't like the idea before...
According to forum rules,posts like 'Thanks' are spam.So on stackoverflow.Moreover,you can simply thank all the posters in one post instead of making a new post for each of them.
If there is really a new forum concept being developed, would be nice to have it added there.
You would have to wait a year,or two or forever.