Facebook’s “Like” button is genius. It’s positive, affirmative, and gives an incredibly simple way to express support for content we enjoy. It requires no deep thought or time, yet sends a reinforcing signal to the poster. It also provides immediate feedback on what your group of friends in the aggregate enjoy.
Those are nice perks, but the real value is that the button acts as a check on the overall quality and tone of Facebook content. Everyone wants to earn likes. But since there is (mercifully) no dislike button, you have to frame negative content up the right way to get liked. No one wants to click like on a story about a house burning down. But the same story, with a line or two about wishing the victims well, is easy to like. The inability to quickly display negative emotion towards a post forces the poster to position and comment on items in a way that makes light of frustrating events, or shows sympathy in tragedy.
Deep, meaningful, terrible, sad and heavy content can and do still get posted. But there is an incentive to put these into some kind of context or perspective with a softer, human touch, or a fun-loving sarcasm that makes a like sensible. This structure is a valuable contribution that alters the ways in which humans talk about the events around us.