Rdio plays catch up, also offers free music on the web

We saw Spotify unleash free music streaming on the Internet yesterday, with today seeing Rdio do the same thing. Rdio has announced that customers can now listen to all of its music for nothing, as long as they don't mind ads.

These ads will include "new feature announcements, messages from partner brands, notifications about exclusive content and other helpful tips." If you don't want to sit through the ads, you can wipe them all away for $9.99 per month by opting into Rdio's Unlimited service.