As mentioned in the other comment, there's no reason to not support Opera. They've spent a significant amount of effort over the past few years to get the browser up to snuff and in most cases will work out of the box if you let it. The problem is that many developers simply exclude it, rather than seeing if it will work.
It's frustrating since I just recently switched to Opera and personally find that it performs great, it feels better to me than Chrome, and overall I really like it. The biggest issue I've experienced and the biggest hurdle Opera has is the wholesale exclusion many sites partake in, usually via a if(opera){ //don't support}, rather than feature testing.
I agree it's not cool to block out browsers like that. Is that what Grooveshark is doing? I didn't test it in Opera.
But then again, maybe they _did_ test it in Opera and saw it didn't work, but couldn't justify fixing it from a cost perspective. So, would you rather have the thing just be all broken or have a sign saying "This is broken in your browser, sorry"?
There is a warning popup displayed telling you that Opera is not officially supported, listing the browsers that are. You can still use the site using Opera, it's just a fair warning saying that Grooveshark as a company doesn't make any guarantees it will work as expected.
You want developers to support Opera because you... like it? As another commenter already said, if opera doesn't even equate to a 1% of your users, you'd be a fool to spend money trying to support a browser most of your users don't even use.
That being said, Opera is a nice browser and has gotten better and better with time. I of course encourage projects that can and should to support opera, but there are plenty of reasons not to support it and in most of those cases they're right not to do so.
It's frustrating since I just recently switched to Opera and personally find that it performs great, it feels better to me than Chrome, and overall I really like it. The biggest issue I've experienced and the biggest hurdle Opera has is the wholesale exclusion many sites partake in, usually via a if(opera){ //don't support}, rather than feature testing.