Largest Maplestory hacking website being sued by Nexon America and Nexon Korea Corp.

That's another interesting point. If they are bringing in several thousand a month, that needs to be declared right? And I'm unfamiliar with US tax code, but can evidence turned up during any investigation here be used in a tax case against them?

Depends where the person lives but if he's a USA citizen yes the IRS can audit him, as can his local state government. As for sales and use tax if it's software it's typically not taxible, however having to update it could be considered maintenance contract which could then become taxable.