[RestlessMind]

You are correct. But then, how does it help me when my feed shows posts just because someone paid Facebook to promote those posts? If a post is going to create bad experience for me, it will be a bad experience irrespective of whether its paid or free.

[brazzy]

The thing is: there's going to be a lot fewer such bad experiences when they cost the person wanting you to have them money. And it may provide an incentive to make promoted content a less bad experience, because in order to maximize revenue, Facebook had to balance the price of promoted content with its acceptance by users: content that is a better experience will cost less to promote because more of it can be shown to users before they get annoyed and leave Facebook.