First steps in Facebook

In the last days, I saw some blog entries about Facebook and I read an article about Facebook. So, I decided to create an account on Facebook.com. Before I created the account I looked on the website and I was very impressed about their developer site. Very much and detailed information. After I created the account I wanted to find friends. Unfortunately, my e-mail address is not supported. Only a few addresses like yahoo.com, msn.com are supported. I have only addresses at t-online or gmx.de. Then I searched for classmates, but my schools are not listed in the directory. I looked for coworkers, but nobody from our company has an account in Facebook. Ok, I like the user interface design of Facebook, but the usage for me is less. I can’t understand that such a company should have a value of 8 billions dollar. But maybe, I haven’t understand the concept of the website.