'Users can just switch off advertising data'

ZUCKERBERG: "There is a setting so if you don't want any data to be collected around advertising, you can turn that off and then we won't do it."

THE FACTS: There is no such single setting on Facebook.

You can limit ad targeting, but it requires several steps, which you may have to repeat from time to time. By default, Facebook shows you ads based on interests you've expressed over the years and the companies you have "interacted" with — for instance, by sharing your email or phone number, visiting their website or using their app.

You can turn off such targeted ads with a single option in your Facebook settings. Doing so means, for example, that you won't get an ad on Facebook for a pair of shoes you just looked at on a shopping website, though you'll still get generic ads.

But that doesn't stop the data collection. Facebook also adds targeting categories based on your demographic information, such as whether you might have a child, your birthday and age, what mobile device you use and even your political leanings — whether or not you've explicitly shared any of that on Facebook.