A large part of Facebook's profits come from what its users will and won't "Like." The like button is useful because it gives Facebook a better idea of what ads you would most likely be interested in.
An experiment by Wired reporter Mat Honan revealed what happens when you throw caution to the wind and start liking everything on Facebook. Instead of picking a social media specialty like funny cat pictures, political posts or viral videos that reflect what he's feeling, Honan opted to become a social media yes man.
You might have already noticed that having a history of likes for a specific topic actually increases the number of posts that Facebook will show you from that topic. If you're an active visitor to my Facebook page, you'll probably receive more of my updates than someone who has never liked or commented on a post.
It's mostly because there's simply too much content on Facebook to absorb in one sitting, so the site shows your post to a group of people it decides are your "close" friends and then gauges how popular it is before showing it to more people. Honan threw everything out of whack by enjoying every piece of content the site could throw at him.
Let’s say you like a story about cows that you see on Modern Farmer. Facebook will immediately present you with four more options to like things below that cow story, “relateds” in Facebook parlance. Probably more stories about cows or agriculture.
Honan's problem was that the "related" posts that appeared after he liked something never stopped coming. Instead of just liking a post about cows, he showed Facebook's marketing robots that he was a cowboy at heart by liking posts about roping, rodeos and ranching equipment.