Users of Internet music discovery service iLike add more music to their song libraries each month than they did before joining the service, according to new research out from the University of Pennsylvania's Wharton School of business.

The Wharton School found that a month after registering for the service, users added 250% more music to their collection than they did the month before they signed up. Five months after registering, users added 30% to 50% more music than they did before joining.

Ilike claims 20 million registered users. Users can download the iLike Sidebar to their iTunes or Windows Media Player and use it through social networking sites Facebook, hi5 and Bebo, for music recommendations, automatic playlists and connecting to other fans and artists.

The research was done between Aug. 2006 and July 2007 and is part of an ongoing study between iLike and the Wharton School.