Most of Facebook's revenues comes from advertising. Microsoft is Facebook's exclusive partner for serving  and as such Facebook only serves advertisements that exist in Microsoft's . According to , an internet  company, Facebook collects as much data from its visitors as Google and Microsoft, but considerably less than  In 2010, the security team began expanding its efforts to counter threats and terrorism from users. On November 6, 2007, Facebook launched , which was an ultimately failed attempt to advertise to friends of users using the knowledge of what purchases friends made.
Facebook generally has a lower  (CTR) for advertisements than most major websites. For banner advertisements, they have generally received one-fifth the number of clicks on Facebook compared to the Web as a whole. This means that a smaller percentage of Facebook's users click on advertisements than many other large websites. For example, whileusers click on the first advertisement for search results an average of 8% of the time (80,000 clicks for every one million searches) Facebook's users click on advertisements an average of 0.04% of the time (400 clicks for every one million pages).
Sarah Smith, who was Facebook's Online Sales Operations Manager, confirmed that successful  can have clickthrough rates as low as 0.05% to 0.04%, and that CTR for ads tend to fall within two weeks.Competing social network 's CTR, in comparison, is about 0.1%, 2.5 times better than Facebook's but still low compared to many other websites. Explanations for Facebook's low CTR include the fact that Facebook's users are more technologically savvy and therefore use  software to hide advertisements, the users are younger and therefore are better at ignoring advertising messages, and that on MySpace, users spend more time browsing through content while on Facebook, users spend their time communicating with friends and therefore have their attention diverted away from advertisements.