geoffrey fowler is the co-author of the report. he joins us from san francisco.s i understand it, this centrals mostly on the so-called user i.d. explain what that is and what you found. >> well, at the core of this is a promise that facebook makes to all of its 500 million users that it will not pass personally identifiable information about us and what we do on the site along to advertisers, marketers and data firms. what we found is that users who were using these apps-- and we checked many of the most popular ones-- they were having their user i.d., which is a piece of information that can be used to look up the real name of anybody on facebook. that user i.d. was being sent along to a lot of different advertising and data companies. >> brown: what does that user i.d., what information goes with that? >> with that is your real name. your gender. the country that you're based in. and then anything else that you've set to public to everybody that you want to share on facebook. so we should be really clear here. we did not find that facebook was allowing adverti