You Tube

You Tube co-founder explains the state of their video ID tools.

Now, when it comes to spotting pornography and graphic violence, and other content prohibited by our terms of use, nothing beats our community flagging. Once a user flags a video, we immediately review it and remove it if we find a violation. But our community can’t identify infringing content. We all know pornography and violence when we see them. But copyright status can only be determined by the copyright holder. That is because almost anyone who creates an original video has the copyright for that work, and such a wide range of copyright holders' preferences vary widely.

Some copyright holders want control over every use of their creation. Many professional artists and media companies post their latest videos without telling us, while some home video-makers don't want their stuff online. Some legal departments take down a video one day and the marketing department puts it up the next. Which is their right, but our community can’t predict those things, and neither can we. The same is true for technology. No matter how good our video identification technology gets, it will never be able to read copyright-holders’ minds.

Interesting. I'll leave it at that.

Also check out some of the features they're testing.