You’ve seen them on your Facebook feed, posts liked by one of your friends claiming a sick and dying child wants a million likes, or a friend will get her apartment rent free if she gets a million likes, or my sister Mallory has Down Syndrome and doesn’t think she’s beautiful. The real story behind these posts is that they are scams to accumulate (or farm) millions of likes, so that the perpetrator can sell the “successful” Facebook page or profile to unscrupulous marketers.
The back story goes like this. Facebook’s EdgeRank algorithm is based on a number of interactions with your page and your content, including likes and shares. Those pages/posts with higher EdgeRanks (more likes, more shares) show up more frequently on Facebook walls. So having a high EdgeRank is a valuable commodity, and one that can be created via like farming, and then sold for a profit. For more details on how Facebook like farming works, read this article from Daylan Pearce Facebook Like Scams.