IDK, I've always viewed the "like" buttons as "Yes, I read your post, found it amusing/interesting, but have nothing to say in response"
yes it's this, and idk if i was clear but it's not a facebook like button, it's part of the forum system. it basically just says like "vellfire, jamie, geodude and 5 others like this". it's just a good way of being like "yeah i agree with this post" even if you don't have anything to add to it. it saves you from quoting posts and saying "this" or emptyquoting.