The rather brilliant Ze Frank, in this TED talk - Making real connections over the web, discusses how technologists [hello, Facebook engineers] aren't very good at providing ways for people to really connect with each other.
"I think of the people who build all of this technology in the networks, a lot of them aren't very good at connecting with people..."
"right? This is kinda like something I used to do in 3rd grade..."
I'm happy to say that his opinion of Facebook 'Likes' aligns rather neatly with my own - Facebook Likes are not engaging.