not only that, they (facebook) will sell your data to whoever pays them. If you 'like' Sears, JCpenny will pay them for all kinds of data on everyone who likes sears and start marketing to that group. Big companies on facebook also have to pay for clicks, likes, advertisement, all kinds of stuff. facebook make tons of cash (just not enough to be worth the original IPO).
Google, gets paid by advertisers, they also mine the web for data, if you search for anything, on the right side of the page is a series of ads, click one and that company will pay google a cent, times that by the millions of people using google and you can see how they make money. Likewise if you search for bike tires, click on 10 links, those 10 companies will pay google, and one of them will get a return on their investment, when you buy a tire from them.
And you are correct, if everyone would delete their account tommorrow FB would be screwed, they make money because they offer a free service and have turned that free service into a gold mine. If everyone stopped using google and went to yahoo google would stop making money. The free service these companies provide is just a way to encourage you to use their service so that your habits, data, profile can be sold (along with everyone elses) to the people willing to pay for it.
__________________
|