Facebook wants to sell every Ad and you on the Web. The social network will show ads to non-Facebook users on other websites.
Companies like Facebook and Google offer you their services for free, but free always has a cost. Advertising pays the bills and the contributors, and these big companies separate themselves from serving up ads that are better targeted than other smaller networks. By tracking you across the web and building a profile (Big Data) that helps which ads you’re going to click most likely.