Reading through this thread, and seeing the opinions that the Like button replaces quite a few +1s (but not -1s), I think it's a great idea and should be expanded to an array of buttons which can make browsing DDF more efficient and useful.
That array could include (in addition to "like") buttons for dislike, lol, ALOL, rofl, bad grammar, speechless, and other emotions and feelings commonly expressed by DDFers.