Also keep in mind that social media/corps don't just use their own data, they also buys search history, credit card transactions, bank information, etc from oth

Also keep in mind that social media/corps don't just use their own data, they also buys search history, credit card transactions, bank information, etc from other companies as well. Granted most of these are "anonymized" but it wouldn't take much effort to link them all together. For example, if you CC company sends your transaction history to FB without any identification information, FB could still know that transaction history by linking your smartphone location data to the transaction history. For example, if they know you were at train station at X time and at a Rite Aid at X time and at a McDonald's at X time, they could go "map" that to a "CC customer data tranche". It is highly doubtful that two people would be at same locations at the same exact times with the same transactions at the same time. FB is big enough to rely on their own data for most of their needs, but selling of your data is big business and everyone is doing it. And as creepy as FB adding your neighbors to your "people you may know", the real creepy part is the B2B part where corporations sell their profiles of you to each other or to governments/colleges/etc. And we are just at the beginnings of "datafication" of everyone. It's truly going to be a brave new world.