From a press release they sent me:
MediaNet, the digital music pioneer has launched an eBook catalog and digital distribution service with 200,000 titles from the world’s largest publishers including Simon & Shuster, Harper Collins, Random House, and others. MediaNet offers a full set of features built on top of digital distribution platform that successfully now supports more than 100 digital music customers delivering an API and Web Components with no upfront costs. This is a game changing opportunity helping to create a marketplace where eBooks are made widely available through websites of all sizes and applications you and I interact with on an ongoing basis while consuming media content.
Content will be in Adobe ePub and PDF and additional formats will be used if needed. More information here.