Slacker Sporting a logo created by artist Shepard Fairey, Slacker provides on-demand access to its music library for iOS, Android and BlackBerry smartphones and tablets. The paid subscription offering ($9.99 a month) enables listeners to search, play and replay specific songs and entire albums from a library of more than 8 million songs or listen in to more than 150 "expert-programmed" stations produced by a team of 70 DJs. Listeners also have the ability to create playlists both on mobile platforms and on the Web and get off-line playback through the ability to cache stations, playlists and entire albums. What may prove to be a notable selling point is sports content provided by ESPN. Basic listeners have access to an ESPN station, while subscribers are able to include customizable ESPN updates in the stations of their choice. A less expensive, $3.99 subscription version and ad-supported free platform are also available. Rdio On Oct. 6, Rdio, a digital music service created by the founders of Skype, announced the launch of a free, on-demand music offering with no ads. The service offers a catalog of 12 million songs, the ability to create custom and collaborative playlists and a variety of artist and label "radio stations." Only an email address or Facebook account is required to sign up; no software downloads or credit card information is needed. Rdio's integration into Facebook's Open Graph platform means users can instantly share and play any song in the News Feed, Ticker or Timeline. Paid tiers -- ranging from $4.99 a month to a $22.99 family plan for multiple users -- allow smartphone access and wireless syncing to listen offline. Stitcher Stitcher takes a different approach to its content and serves as an aggregator of online, third-party content from online radio and podcasts. It can be accessed via a Web browser or through mobile applications. Unlike other services that focus largely, if not exclusively, on music, Stitcher provides talk content from a diverse collection of media outlets that includes NPR, CNN, Fox News, MSNBC and the BBC, as well as thousands of smaller, independent outlets (some content is subscription-only, as per the provider). More than 6,000 shows are available as the company looks to pull in a share of the more than $5 billion in revenue talk radio advertising generates each year. The free service has 3.4 million registered users and is available for iOS, Android, BlackBerry and webOS.