People on this board criticized this 9-0 decision, but the way it was written, it just basically said "if you intentionally faciliate the violation of copyright laws you may be held liable."
As a legal matter, it's pretty difficult to find fault with that holding. Which is why not a single justice dissented.
The Internet is an international market place. A Russian, for example, could develop and sell the download software from Russian sites. If the Russian government was getting a cut, there is no way our courts and laws could shut the sale of the illegal software down. And if millions of people are using it there is no way the government can stop its use by normal law enforcement methods.
If millions of people are downloading one could not get a jury to convict. Local state and National governments that tried to enforce such a law would sooner find new leaders elected who would not enforce the law.
The only solution is some sort of electronic traffic cop on the Internet. A software cop housed at ISP locations that would be able recognize illegal transfers and stop them from being completed.
Government could force ISP's in the USA to install packet sniffing software that could catch illegal transfers and send them to that big bit bucket in the sky. That is the only workable way for government to prevent illegal transfers.
Anything short of that solution is doomed to failure.