After having been sued by Sony Music Entertainment, Arista Music and Warner Bros Records, it seems the people behind Grooveshark have decided to settle (or maybe they lost, I'm not sure), and have closed down the website. The homepage now has an apology to the users of the site, stating that they "failed to secure licenses from rightsholders for the vast amount of music on the service", and further mentions a settlement agreement with "the major record companies", but does not state who these companies are (I think we can all take a good guess, however).
They have further handed over "ownership of the website, our mobile apps and intellectual property, including our patents and copyrights". I guess it goes without saying that mobile apps should be removed immediately.
Unfortunately, I can't copy/paste the message, as it's encoded in a *.png image (and I don't have time right now to re-type it manually), so I'll just attach a modified copy of the image (the original has a transparent background, which makes the text hard to read. I've added a black background, but haven't modified anything else).
RIP Grooveshark. You will be missed.