what is facebook...explain please

Facebook is a social networking site. It does NOT pay anything, even for referring people to it. There is (or was) at least one Facebook application which pays money for tasks, a bit like the Tasks here or Amazon's MTurk. I'm not sure if it is still operating, though, because I can't find it in the Applications.

facebook is colpletly free, it's a social network, a site full of people from all over the world, there you can up photos, images, write about your life, you can talk with other people, maybe people that you know in the real life, and you can talk and meet other people that you don't know in the real life. I'm a member of facebook since the last year. On facebook i've a lot of friends, real friends that i have met a lot of times in the real life. On facebook there is my girlfriend too.