Ugh, no. Please don't implement a Like button. I don't care if other people "like" something or not. If they have something useful to add to a conversation (either positive or negative), then let them post.
Besides, those folks who like the "sound" of their own "voice" will still post stuff like "Yeah, I agree" or other <5 word responses that add little to conversation. I don't think they'll switch to using a "Like" button, so it probably won't cut down on the pointless posts.
Of course, I lurk 99% of the time, so perhaps the whole "don't respond if you have nothing valuable to add" is just a reflection of my own personal nature.
I'll survive if it's implemented, but it does seem pointless to me.