Microsoft's long-awaited portable music player Zune today goes on sale in the US; in a market dominated by Apple's iPod.
While Microsoft's PC-based Windows software has trumped Apple's computer divisions, the iPod is the undisputed global king of the MP3 market, owning a 75 per cent share in the US and more than half on a worldwide level.
But the software giant is confident that the $250 (£131) priced Zune will prove a success, despite concerns that Microsoft has harmed its own chances with some controversial technology decisions.
As well as music uploaded from users' CDs, the device is only compatible with songs bought directly from its flagship online store; Zune Marketplace.
This means Zune owners can not buy music from Napster, AOL or Microsoft's own previous MSN Music outlet, not to mention Apple's iTunes.
Zune has received praise for its large display screen, built-in radio and wireless capabilities, but the restrictions on song sharing have disappointed fans.
While users can wirelessly transmit music to another owner's device, no one song can be sent more than three times and can only be stored by the receiver for a maximum of three days; even music to which the sender holds the copyright to.
But speaking ahead of today's US launch, Alex Zubillaga, executive vice president of digital strategy and business development at Warner Music, one of Microsoft's industry partners in the Zune venture, said: "Music has always been experienced in a community, and through Zune, Microsoft is building a robust and unique digital music community platform that enables consumers to share, sample and download their favourite music.
"Warner Music commends Microsoft on the launch of the Zune digital media player and Zune music store, and is proud to be a content partner of this important addition to the dynamic and growing digital music space."
No official release date for Zune outside of the US has been set, with the music player not thought to be arriving in Europe and Asia until late 2007 to early 2008.