It's called Grooveshark, and I've never understood why more people don't use it.
The site, owned by Florida-based Escape Media Group, is so good that it's not surprising it has been sued by various major music labels for copyright violations. It is engaged in an ongoing legal battles with Universal Music Group, Sony Music, and Warner Music Group, though it settled out of court with EMI Music Publishing and just this morning signed an amicable pact with Sony/ATV, according to Digital Music News.
The legal onslaught felt like "getting punched in the face 10,000 times," CEO Sam Tarantino told Mashable in April.
Nonetheless, the site remains legal and claims 20 million users. It has major advertisers too. It feels pretty legit.
What's so great about
The site licenses or shares more than 15 million songs, which means it has most things you're looking for.
It lets you search for and play entire albums. This simple feature is not available on Songza and
You can listen to as much music as you want for free without any audible ads. This features puts to shame Spotify and Pandora, which both insert audible ads every few songs for non-paying listeners. Like Songza, there are visual ads that appear on the site for non-paying listeners. Visual ads are easy to ignore and do not kill the mood.
It has genre radio and recommendation features too. Like those other streaming sites, Grooveshark can help you discover music and it can play a nice assortment of music if you don't want to choose yourself. I don't know if its recommendation engine is as sophisticated as Pandora's, but it works fine.
There are all kinds of social aspects to Grooveshark too, though I haven't explored them. I'm perfectly satisfied with a site that lets me play pretty much any album I want for free without ads.
The only downside I've found is that Grooveshark has limited mobile capabilities, due to restrictions from Google, Apple, and Facebook. It has a full HTML5 player, however, which means that you can access it on an Internet-connected smartphone.
The idea that Grooveshark, like other streaming sites, hopes to pitch to music labels is that listeners will use it to find music that they eventually buy. I behave in this way occasionally, having gone on to buy several albums that I first listened to on the site, doing so so that I could listen to them offline and because it seemed like the right thing to do (see the music listening habits of other BI writers here).
Try out Grooveshark as long as it's still legal.