...While on facebook, users willingly and explicitly define their interests, dislikes, personal information, etc. Facebook doesn't need to 'extract' that infor

...While on facebook, users willingly and explicitly define their interests, dislikes, personal information, etc. Facebook doesn't need to 'extract' that information based on browsing information (although it probably could, given the number of sites that share information or use the fb api, and the links that users share with each other) and user posts (statuses, wall posts, notes). Facebook has far more information available than reddit, so yes, it should be able to target ads much better.