This has a lot of implications for fanfiction and internet censorship, mainly in the realm of copyright law.
It's a legal case going before the Supreme Court. Guy contacts some relatives of his in Thailand. They legally buy locally made college textbooks, no copyright infringement, purchased from the publisher. All good. They ship them to Guy in the US. All legal, all good. Guy now owns these books. Still good. Guy decides to sell these books. Still legal under 'first sale doctrine' - copyright owner got paid first time they sold it and now have no claim to further sales. Guy sells over a million dollars of books on eBay. Book publisher goes apeshit, claiming Guy is breaking the law, because apparently there is a conflicting law that says you can not resell (or redistribute) a copyrighted work without the copyright owners permission.
As we in fanfiction know, due to the frequent idiotic claims about piracy and/or copyright infringement that crop up even when we write or publish entirely profit-free. It's something to keep an eye on.