Well there's definitely a fair amount of overlap between us and all of those services.
How we differ from Lala:
-I'd say we're pretty similar, but we do away with the "silly" notion of having to pay to listen to the same song more than once.
How we differ from Raphsody:
-My understanding is that they are pretty much a purely subscription based music service, and their subscription prices are rather high.
How we differ from Spotify:
-Spotify is also pretty similar to Grooveshark out of these, with a major difference being that they are only available in a handful of countries, the fact that you must install their software to use their service, and I'm told the experience for non-subscribers can be pretty lousy, with lots of ads all over the ap, and annoying audio ads. I haven't had the chance to use Spotify much, since it's not available in the states yet and I haven't bothered to hunt down the proxies I would need and get that all set up.
Basically with Grooveshark, you can just go to
Grooveshark - Listen to Free Music Online - Internet Radio - Free MP3 Streaming and search and listen to whatever you want for free. The main site is flash based (written in Flex), and it feels more like an app than like you are browsing the web, which makes for a better user experience in my opinion. You don't need an account to use the site, but you will need to create one if you want to create playlists, favorite songs, or add songs to your library.
Subscribing is totally optional, and subscribers get to use the site ad-free, access to a desktop version of the app, more themes, a VIP badge, higher limits on favorites and library size, and the ability to try out the newest features first, including the mobile apps, but the key is that you do not have to subscribe or even log in to find music and listen to whatever you want.
We also have an artists section to help artists & labels promote themselves, get in touch with fans and of course monetize, but I don't work on that part and I don't use it because I'm not a musician, so I'll leave it at that.