Does anyone know the "Like" function on other vB boards?
It isn't like the "Reputation" function which is on display and follows you around the site. It only applies to specific posts, and you can't use it negatively (there's no "Dislike" option!). It's just a way to say you appreciate a post, even if you don't reply to it. This would cut down on the number of "+1" type posts that take up room on threads. It can also lead to greater civility amongst users because inevitably people will "Like" the occasional post from someone they usually disagree with, which can ease tensions.
All in all, it's a very light function that is not that intrusive or flashy, but does some good. I think it would work well on GG.