I can feel the upcoming hate going to flow from that button.
The spin Zuckerberg is putting on this is ridiculous, stating it will be used to express empathy for statuses that 'Like' is inappropriate for, something like 'In the hospital, fingers crossed for my baby :(' is a direct contradiction to it being used for when someone shares a Nickelback song.
I think the the implementation Slack went with solves this problem more eloquently. Sure, you'll have a bunch of emoji's everywhere, but that's a hell of a lot better than liking/disliking something that requires a more delicate emotional response.
Like an emoji :P
lol, that was a bit asinine wasn't it? But really! You can say much more with an emoji than you can with basically a +1 button.