Advertisers have long understood the value of facebook's unprecedented trove of personal information. They can serve ads using highly specific details like relationship status location employment status favorite books movies or Tv shows and a host of other categories. For example an Atlanta woman who posts that she has become engaged might be offered an ad for a wedding photographer on her facebook page. When advertisement are served to finely targeted subsets of users the response is much more successful than than traditional types of advertising A growing number of companies both big and small have taken notice: in 2011 Facebook made $ 3.2 billion in advertising revenue which constitutes 85 percent of its total revenue The rest come from the sale of virtual goods and services principally Zynga game