> Of course, they won't have any of your data if you don't have an account
Facebook can indeed. Your name even without an account can be tagged into photos and status updates by other users. Those photos contain location data. And of course the accounts of other users in the same photo as you contain a wealth of data about their locations and interests and one-degree-further friends, statistically speaking much of which will also apply to you.
Whether Facebook has the ability to automatically aggregate such sparse data into something useful is an open question, but the data does exist. Unless you somehow never let yourself get photographed or mentioned by anybody else who does use Facebook.
Facebook can indeed. Your name even without an account can be tagged into photos and status updates by other users. Those photos contain location data. And of course the accounts of other users in the same photo as you contain a wealth of data about their locations and interests and one-degree-further friends, statistically speaking much of which will also apply to you.
Whether Facebook has the ability to automatically aggregate such sparse data into something useful is an open question, but the data does exist. Unless you somehow never let yourself get photographed or mentioned by anybody else who does use Facebook.