I think that the 'like' feature is a good addition to this site.
My only issue with it has already been pointed out and being worked on (you can't unlike a comment).
As someone who does not post here frequently, and can be a bit strapped for time, the like button is a good way to inform the person who made the post that I like it.
Sometimes a post can be so succinct that it does not require a response, however, getting likes to indicate that the post has been acknowledged is certainly a good thing.