What PG says is 100% true. I say this having done a startup in the space.
In a nut shell, you need roughly $1M upfront for legal fees to negotiate with the big four record labels (for an interactive service, not a non-interactive service like Pandora).
I guess I understand what you mean. Though I wouldn't use the words interactive/non-interactive. Pandora is quite interactive in a UI sense, even though you can't select tracks directly.
If it's lasted this long it will probably keep going for some time yet. They have a pretty clear song takedown policy, so any music being shared on grooveshark is likely being done so with the full consent of the label.
Grooveshark is also paying the music owners royalty from a share of their ad revenue.
I've done Daring Fireball several times for The Little App Factory (tlaf.com). While the immediate response is fairly good, I believe the real payoff is more long term. Publishers and the hardcore mac community notices what's advertised there and may be more inclined to write-up your product or service.
Note that you can bootstrap your way into this sort of effect by figuring out what your influencer of choice (blogger, NYT journalist, whatever) is likely to be searching for and then putting AdWords against it. Since they're often a bit smarter than the average bear and using longtail or obviously non-commercial queries, these are generally cheap as sin.
Then, rather than a landing page for a commercial service, you direct them to a page designed to elicit coverage of whatever it is that you're offering.
An example that I don't know that any SEO did so they won't be POed if I mention it: you know all the Facebook privacy hubub right now? I think it is quite likely that someone is out there looking for [facebook privacy quote]. If you're going to spend thousands on PR, why not spend a few tens on AdWords and have something responsive to that. It is very, very cheap if your page influences coverage at the NYT or pulls in links from bloggers.
The site has 100k visits a day (started ~August '09), and a considerable amount of financing. We're looking for somebody to lead the day-to-day development for a good amount of equity or pay (your call). A good understanding of what makes a "complete" and usable consumer product is critical. Also, the backend is python / django.
And obviously, if you like music too... we'd really love to have you!
Almost all of life is arbitrary and meaningless. Denying this is not particularly enlightened, and ultimately tends to get rejected by the intellectually curious. On the other hand, seeing absolutely no meaning results in wasted time. The least bad answer seems to be leading a balanced life, with a few elements that are very important, from which meaning is created.
Richard Dawkins has a quote along the lines of, "Why do we have to look at a beautiful planet and demand a reason behind its being here? Can't we appreciate it for what it is?"
So it is with life. Perhaps in the long run we'll all be dead and the universe will cave in, but in the meantime the things we do and say matter, and there is beauty in the world to appreciate. So I went to the boardwalk with my father and brother and we all had a terrific time, and having a good time was reason in itself to do it.
Once you give up the religious/gamers' view that everything you do has a score, you can appreciate things for what they are rather than for any ultimate result.
In a nut shell, you need roughly $1M upfront for legal fees to negotiate with the big four record labels (for an interactive service, not a non-interactive service like Pandora).