stacybro writes "Wired is running an interesting article about amateur astronomers tracking "black" satellites."
From the article: "The observers, who congregate on a Web site called Heavens-Above and a mailing list called SeeSat-L, have amassed an impressive collection of information and expertise. For two decades, they have played a high tech game of hide-and-seek with the US's National Reconnaissance Office, a secretive satellite agency. By coordinating their efforts, amateur observers in Europe, North America, and South Africa monitor satellites at different phases of their journeys and extrapolate the precise dimensions of their orbits."
This is in addition to the ones we know about
and even the ones we think we know about