An example of domain parking for $$$ I register phoofoobitz.net today. Tomorrow a parker-bot registers phoofoobitz.com Next year when I determine I'd get a lot more hits with .com than with .net I'd need to pay bucks to the parker to get it.
Sex.com was a high level TLD that was parked for years. Good example of how a domain squatter registers a TLD, sits on it until someone wants to register the domain, finds it's taken and has to pay $20 Mil to get it.