Since people are reminiscing on the loss of their favorite music services from the past, I'd like to add We Are Hunted [1] to the list.
> proprietary search technology which continuously scanned the Internet to identify the hottest new music in the world.
For a short period is was the best way to discover new unknown music. It was bought by Twitter, folded into Twitter music (even though they never created a comparable feature) and killed along with it.
If anyone knows anything like this that exists today, please let me know.