Here's a fairly interesting article about "spyware" being installed by Blizzard along with their World of Warcraft game. Their interest in stopping cheaters very closely mirrors the poker sites' desire to stop bots.
According to the article it "sniff[ed] down the email addresses of people I was communicating with on MSN, the URL of several websites that I had open at the time, and the names of all my running programs, including those that were minimized or in the toolbar." More at
Article at Rootkit.org
Martin