I had my game theory textbook pirated today on Scribd. This was the first time that ever happened. The DMCA takedown notice did not take long to write, and Scribd removed the book within eight hours. Overall, it was a painless but not so fun diversion.
Anyway, I doubt I would have noticed it at all had I not set up a Google alert. Essentially, Google sends you an email whenever a new website pops up using the search terms you desire. If you have your name or your book title set up in the alert, you will know within 24 hours when something like this happens. It is a free and easy way to fight piracy, so I strongly suggest you set up an alert for yourself.