I am not a facebook user, how do they camouflage ads as posts from friends?
"John Smith likes Wall Street Journal" with the headline and picture from a recent article.
It appears in your news feed like John Smith recently liked Wall Street Journal, or that article.
In reality they probably clicked the like button years ago, and Facebook just continuously recycles that in your news feed, in a way that appears recent.
Bob liked Soylent a year ago and has had no recent interaction with it that would merit showing up in the newsfeed. That particular one is funny because Bob swore off Soylent after a few months and just didn't bother to unlike their page.
Of course, not everyone will actually ask Bob for his opinion, but if I really cared about the fact that Bob liked something, and that was a factor in my purchasing decision, I would probably ask him about it, myself.
As a whole, it really dilutes the news feed because half of it is actual "news" from friends (when they recently posted, liked, or shared something) and half is advertisements disguised as posts with my friends' endorsements written at the top because they liked NYT or KFC's page five years ago.