Skeptical Shopper: The Risks of Social Networking Games

If you have a Facebook account, you're probably familiar with Zynga games like Farmville, Mafia Wars, and Vampires Live. Your live feed may be clogged with updates from friends participating in these games, or you're trying to make the workday go faster by playing them yourself. They seem harmless enough--but TechCrunch.com has unearthed a video of Zynga CEO Mark Pincus saying the company "did every horrible thing in the book" to make money off of players. What "horrible" things are players susceptible to?