The share price of Facebook fell about 20% after the company revealed what everyone already knew. FB both uses and sells customer data as a core element of the company's business model with respect to revenue generation. This had to be the worst kept secret in the history of mankind. But let's not just point the finger at FB. In addition, to selling advertising space on their pages, most if not all web-based companies that offer their services for free, do virtually the same thing. Since it is common practice, maybe this has something to do with the fact that the share price of Facebook is up about 40% since the April low.
