A Pew Research Center survey has found that while 74% of US adult Facebook users didn't know that Facebook kept track of their interests and traits for ads, just over half were uncomfortable with the practice. Facebook knows your age, gender and location, along with what you post, the pages you like and the businesses you check into on the social network. All that information helps the company determine what ads to show its 2.3 billion users. "Americans, being Americans, say that it matters, but they behave in a way that doesn't indicate that it matters," said Pew's Lee Rainie.
What can you do about it if you are concerned? Facebook users can view their "ad preferences" page to see what the social network thinks their interests are and why they're seeing a given ad. This list can include users' political leanings, hobbies and even the type of smartphone they use. Facebook users can also remove an interest from that list to change the type of ads they see on the social network.