Oh please no. What is the point? I'm sorry, but Facebook is taking over the world these days, and I personally don't want to see it spilled into PC too. I read Audy's post, because I tend to see where you come from, Audy, but, if you like a post there isn't anything stopping you from quoting it and replying. I don't think it's anything like rep either, but it takes away from the community aspect of PC. If people just go around "liking" posts instead of actually replying to them, it becomes counter productive.
Above all though, probably about 70% of the planet uses Facebook, this suggestion was fed by it, I see Facebook on every ad and magazine and cat's forehead, I'd really rather not see one of the selling points of Facebook dragged onto PC too. Look, I know it's not a big deal, but I personally come to PC because it gets me away from social networking sites. I was once for this idea, until I realised that this would become annoying to a lot of active users. Unless there is the option to turn it off and hide these like buttons, I'm against it. Members have the option to reply, post vm's, pm's or post comments.
Perhaps I don't like a post, maybe I love it, maybe it inspires me, maybe it's one of the best posts I've ever read and I just want to convey my jubilation having read the post to the user by replying to it and being on topic. But you know what, there's a Like button, I'll just click that instead. That could easily become the mentality of members. As I say, it seems pretty popular, just give us the option to hide it maybe? I'd just hate to see PC conforming and being just another one of those millions of sites that resorts to drawing inspiration from Facebook.