Microsoft security engineer Billy Rios tells the Wall Street Journal that some of the best scams are the ones that phishers play on each other:

Hackers write software that automatically designs “phishing” websites — those sites that look like a bank’s site but are really controlled by a hacker. Rather than operate the sites themselves, they sell the software to a newbie, who runs the scam. But the software is programmed to send a copy of whatever information it collects back to the author.