Interest in Microsoft's Zune media player appears to be diminishing, if Amazon.com's sales charts are anything to go by. This despite grabbing the number two slot in the US retail market immediately after its 14 November launch, according to figures from market watcher NPD.

NPD's numbers - published yesterday, according to EETimes - show Microsoft's player accounted for nine per cent of unit sales and 13 per cent of revenues in the seven days to 17 November. That placed it just ahead of SanDisk but well behind the iPod's figures of 63 per cent and 72.5 per cent, respectively.

NPD categorised the Zune launch "a success", achieving a decent share of the market despite its relatively high price.

Separately, a survey carried out on behalf of the Reuters newsagency revealed that a third of media player buyers considering a Zune purchase were looking to upgrade from a player they already own. That said only seven per cent of those surveyed, when presented with a list of players, said they were keen on a group that included the Zune.

By contrast, 80 per cent said they'd pick an iPod. Of that number, only 18 per cent said they were upgrading.

Zune's relative strength in the upgrade market lends weight to the argument that the device will hit Microsoft's Plays For Sure hardware partners more than it's going to hurt Apple. The iPod maker is clearly appealing to many more new users, so it's business is still coming through growing the market than canibalising it.

Apple's player today dominated Amazon.com's electronics best-sellers list, let alone the more specific MP3 players list, which contained just three non-Apple devices: two SanDisks - at chart positions six and eight - and a Creative, placed tenth.

Zune didn't even make the top 15 - the black version was listed in 17th place. The brown model came in at 37, the white one at 76. Amazon.com's numbers are updated hourly, and positions change frequently. But iPods tend to cluster around the top ten. ®