An online music community, where 24,459,879 fans were logged in just minutes ago, could be under threat.
Project Playlist is being sued by nine of the major record labels for "massive infringement" of copyright.
The site lets visitors search for songs and share playlists; and gets nearly 9.5 million average page views per day.
The lawsuit, filed by music big hitters including Warner Bros, EMI and Virgin Records America, was prompted after it's claimed the site started "optimising" tunes for iPhones and iPods.
The site also allows users to embed playlists on social network sites such as MySpace, Facebook and Blogger, claim the lawyers.
"In short (Project Playlist's) entire business amounts to nothing more than a massive infringement" of the record companies' copyrights, the record companies said.
They want to stop Project Playlist from offering free music and are also seeking unspecified damages.
Project Playlist's team are keeping very quiet in the meantime.
They're probably trawling the Yellow Pages for a lawyer.