Analysts at iSuppli expect the MP3 player market to expand to 230.8 million units by 2009.

DigiTimes is carrying an editorial piece by iSuppli senior analyst Chris Cotty, who relates the history of the market since 1993.

Cotty points out that the MP3 player market grew 250 per cent to 128.7 million units in 2005, up from 37 million in 2004. "Apple continues to dominate the market for MP3 players," he writes.

The analyst points to SanDisk as the most powerful potential Apple competitor, partly because it has its own available technology, and also because it manufactures its own flash memory for devices.

Maintaining its market dominance may be a complex affair for Apple: "One key challenge that Apple faces is iTunes' contract renewal with record labels, some of which are expressing an interest in variable pricing, making consumers pay larger fees to buy the more popular songs. Apple is resisting this move, and user studies certainly suggest that consumers likely would respond to any price increases by reverting to more piracy," he writes.

Some musicians argue that Apple's set fee structure puts artists under pressure to write shorter songs. Artists with 23 songs on an album mathematically stand to make more sales than those with fewer but longer tracks, they reason.

Some critics of Apple's set price policy also point out that it makes no distinction between every day tracks, rare or hard-to-find tracks, or tracks of great cultural or musical significance.