Yes, a copy of Rihanna's latest album could slip through but it would have to be hidden under a different name for that to happen, then how are people going to find it? If you want to listen to Rihanna on Grooveshark then you type "Rihanna" into the search engine.
> Worse, the more you tighten up that code, the more Prof. Ushers you ban. We have Google blocking access to bird songs already. And I know you know how skilled their coders are.
That's completely different though, context is important. Grooveshark is a "free Spotify", Youtube is a video community and a video hosting platform. Grooveshark has one use case, Youtube has many. For example Youtube developers work to catch music that is a part of a video that isn't necessarily focused on the song, that would never happen with Grooveshark. Also external sites embed Youtube uploads and use that to host music, can't be done with Grooveshark.
The fact is you or I (or any slightly competent developer) could build a system that could block almost every single possible upload that labels/artists don't want uploaded, Grooveshark CHOOSE not to do this.
As a user you need to know what you're looking for, you need to tell the search engine what you're looking for, if you're looking for Rihanna you don't type "r1h4nna4534535" and so if someone uploads the latest Rihanna album with the artist name "r1h4nna4534535" who is going to find it? Hell, even if they did there are solutions to that problem.
Of course they don't, it's not their job to police someone else's copyrights. Do you think Escape's shareholders wouldn't sue the officers of the company for breach of fiduciary duty if they discovered they were spending company funds to prop up some other business? If you own a copyright, it's your own job to enforce it. Why should copyright holders get to freeload off Grooveshark's work?
That said, please understand that I do sympathize with you about artists getting screwed. I just don't want to see solutions where we merely pass the buck to someone else without getting at any of the underlying problems. Frankly, I believe that the solutions lie more along the lines of making sure that artists get their cut, rather than restricting who can listen to music and how. But I certainly don't have all the answers here.
And you have to cast it widely to even put a dent into things, because you only need one copy available for everyone to copy it. Just one false negative out of millions of songs and everyone copies that one that slipped through. They need exactly one search result, not 100. Google does all that you say and more on YouTube. Let me know how hard it is for you to find infringing content there (hint: not very)? Sure, they play whack-a-mole with it. But that damned mole keeps popping back up and it's not hard to find a mole that hasn't yet been whacked.
Worse, the more you tighten up that code, the more Prof. Ushers you ban. We have Google blocking access to bird songs already. And I know you know how skilled their coders are.
You should have at least banned the cryptographic hashes of anything that got DMCA'd. At least that has few false positives (assuming few DMCA notices are false). It's vulnerable to deliberate infringers making tiny changes to the files, sure, but I'm unaware of any solution that isn't. And you're required to ban anyone who is a repeat infringer anyhow. But we're playing whack-a-mole. More moles always pop up.