I feel like a lot of posts are quoted by people just to say "love this" or a thumbs up sign...it would be cool if there was an ability to "like" a post like on Facebook.
next to the post, a mod will weed those out. They can be a mild annoyance for many to read and post count padding is still something the mods keep an eye on.
I spend most of my time in the photo sub-forums on MR. Short quotes drive me nuts. +1 and Nice pic don't add anything to the experience. I want to know why a photo is pleasing so that I can incorporate that into my own photos.
A Like button is not helpful. It doesn't encourage the kind of exchange of knowledge that makes MR such a great place.
Anything remotely resembling FB gets my thumbs down, also.
I wouldn't see the point. This is after all, a discussion forum, is it not? Inviting people to choose between pressing a "Like" button instead of actually typing out their thoughts and inputs, would just be pointless.
I think it's a good idea. While having separate posts just to say "+1" clutters the thread, sometimes people do want to express agreement, and this is an unobtrusive way.