Bloomberg: Google’s YouTube, which has signed up partners for a new paid video service, may find out by early next year whether its own Internet stars really are as valuable as those in Hollywood. Partners accounting for more than 90 percent of YouTube viewing have signed on to the paid service. While the lineup incudes home-grown celebrities and music videos, YouTube so far doesn’t have TV networks such as Fox, NBC and CBS. The networks still have time to sign up. YouTube, has targeted a roll-out of the paid service by the end of the year.