Of course, as with any law, YouTube's legal status might not be 100-percent airtight. The law suggests (in §512(c)(1)(A)(ii)) that YouTube might be liable if, in the absence of notice, it is "aware of facts or circumstances from which infringing activity is apparent." Also, YouTube provides a search, and maybe it could be liable for that. There might be enough to make trouble in the hands of a judge who really hates "that whole Web 2.0 thing."
But we may never find out. What's really interesting is that the content industry actually likes §512 more than anyone will admit. The notice-and-takedown system gives content owners the twin advantages of exposure and control. When stuff is on YouTube, the owners have an option. They can leave it posted there, if they want people to see it, and build buzz. But they can also snap their fingers and bring it all down. And for someone who is juggling her desire for publicity against her need for control, that's ultimately a nice arrangement.
Stated otherwise, much of the copyrighted material on YouTube is in a legal category that is new to our age. It's not "fair use," the famous right to use works despite technical infringement, for reasons of public policy. Instead, it's in the growing category of "tolerated use"—use that is technically illegal, but tolerated by the owner because he wants the publicity. If that sounds as weird as "don't ask, don't tell," you're getting the idea. The industry is deeply conflicted about mild forms of piracy—trapped somewhere between its pathological hatred of "pirates" and its lust for the buzz piracy can build.
But what about Mark Cuban's copyright argument? Why isn't YouTube in trouble in the same way Napster and Grokster were? The first difference, as indicated, is that Napster simply wasn't covered by the §512 safe-harbor law, and YouTube is. Napster wasn't "hosting" information at the direction of its users, but rather providing a tool for users to find and download predominantly infringing content. It may sound odd that Napster gets in more trouble for helping you find illegal stuff than YouTube does for actually hosting it. But that's the law and why YouTube should really, really thank its friends at Bell.
There may also be deeper differences. If the Internet were not a bookstore, or tubes, but rather a red-light district, YouTube would best be imagined as the hotel, and Napster, well, the pimp. YouTube, like a hotel, provides space for people to do things, legal or not. It's not doing anything illegal itself, but its visitors may be. But Napster, everyone more or less now admits, was cast as the pimp: It was mainly a means of getting illegal stuff. Right or wrong, we seem to accept the benign vision of YouTube as an entity which, unlike Napster, was basically born as a place to showcase stupid human tricks.
The upshot is, as YouTube goes mainstream, copyright's etiquette rules are becoming clearer. Yes, these sites can make it easier to infringe copyright. But so long as that's not the principal aim of your company, you have more breathing room today than you once did. And under the emerging regime, if you do cause infringement, you have to be nice about it and make determined efforts to stop it. Apple has learned that dance well, even as its iPods make swapping music all the more part of being American. And YouTube has, in turn, learned from Apple the early lessons of Napster: You can act out in cyberspace. Just don't be a copyright pimp.