More and more companies are signing onto Facebook. Hardly anywhere else can they appeal to so many prospective customers so directly. In effect, that's turning fans into a commodity. Just how much are they worth? Users who click on a company's "Like"-button and become "fans" are often satisfied and regular customers. They're also more likely to bring the company's products to their friends' attention. As companies realize the potential, they are expanding their social-media activities. The idea is, the more fans, the better. Some companies are even buying fans. They can collect thousands for just a few hundred euros overnight. But this is no guarantee of success. Interaction with those fans is crucial.