While looking through the visitor statistics for this website, I noticed something. One of the referrers (people clicked links from these pages to get to this blog) was:
The page appears to be an internal document, inaccessible from computers outside the Facebook network. Although its contents cannot be retrieved, the URL provides some insight into the world of Facebook. It turns out there is someone at the company keeping track of related websites, such as this one. There is even a wiki set up to assist in the process. A cause for concern?