It's amazing to think how much the word 'like' has changed in the 10 years Facebook has been around. It used to mean that you had a positive feeling toward something. Now it's about clicking an online button, even if you don't always 'like' the content.
For example, you might not like the announcement that your friend's pet just died, but you might click "like" to acknowledge that you've read the post and that you're thinking of them. In fact, liking posts is something of a reflex for many people, and it's a reflex that scammers are taking advantage of. Welcome to "like-farming."
Like-farming is just what it sounds like. Scammers post a story on Facebook for the express purpose of cultivating likes and shares. Based on the way Facebook works, the more likes and shares a post has, the more likely it is to show up in people's News Feeds.
This gives the scammer more eyeballs for posts that trick people out of information or send them to malicious downloads. The big question, of course, is why Facebook doesn't stop these posts before they get too big. And that's where the real scam comes in.