Working in the Israeli city of Netanya, next door to our offices was a spam operation with roughly 30 employees. One day they weren’t there anymore.They were blog comment spammers, but officially were doing Search Engine Optimization or SEO. Instead of optimizing content, they posted illicit comments on many blogs with commercial or misleading messages leading to their clients’ web sites, mainly for the purpose of increasing their clients’ web sites visibility in search engines such as Google. They would do this using an illegal tool such as botnets, and make quite a bit of money.The reason for their disappearance soon became clear; nearly all their clients were gone. A law was passed in the United States which addressed online gambling operations (“Unlawful Internet Gambling Enforcement Act” – UIGEA). As a result, the public gaming industry ceased accepting online wagers. More than that, UIGEA addressed processing payments to and from Internet gambling sites. In a day, most of US-based gambling web sites ceased to exist (others moved over-seas, although quite a bit of the world’s credit processing is done by US firms). This effectively caused the death of numerous black hat SEO companies-comment spammers. Perhaps the UIGEA measure against processing of payments proved too difficult to overcome. Not being a lawyer I can’t say exactly how UIGEA caused this death. No matter, US online gambling operations were effectively destroyed.
http://blogs.zdnet.com/security/?p=720