If this had rolled out on Apr. 1, there would be no question that Napster.FM had to be a prank. Instead, the Napster equivalent is a streaming music library that apparently grabs music from YouTube and streams it via the site at Napster.FM, along with the chat, Hot List and user features that the OG Napster once had. They've taken the liberty of pre-loading "Never Gonna Give You Up" by Rick Astley, a la the infamous Rick-Rolling song, adding fuel to the prank idea. However, a quick test reveals both Gorillaz and Bassnectar songs were available, "Dirty Harry" and Vava Voom both were streaming through my computer. It seems legit.
Napster .FM was created by Carnegie Mellon student Ryan Lester, who is taking a sabbatical to work at Space X ... and apparently to do Napster FM. He said "As far as the streaming music, I'm essentially just grabbing existing content on YouTube based on metadata (titles, artists, etc.) from the Discogs database." He's remixing for the modern age.
The site isn't affiliated with the OG Napster that was bought out by Best Buy, but doesn't seem to worry about the copyright issues using the Napster name. Check it out for yourself at napster.fm, you can create accounts and do social music stuff with other users ... even the real-time chat that had Napster had back in the day.
TechCrunch is saying that "The best part about it is that it’s open source and can be set up by anyone, in case it ever gets shut down," mentioning that it also has the ability to live in the cloud, so you'll be instantly synched on all of your devices.