Lala is a music streaming service that allows users to listen to their personal music collection through a web browser. It started in 2006 as a CD trading service but transitioned to streaming in 2007. Users can upload MP3s from their computer library and stream them on any web-enabled device for free without ads. They can also purchase songs from Lala's catalog for 10 cents each web stream or 89 cents for mp3 download. The service includes social features like seeing friends' collections and getting recommendations.