You might think that a dedicated player like Napster or Spotify would hold claim to the largest base of customers for subscription-based music services, but quite the contrary -- it's actually megacarrier Vodafone, which offers access to around 2 million DRM-free tracks at a variety of price points in Germany, Greece, Ireland, Italy, Netherlands, Portugal, Spain and the UK, a library that it says will grow to some 6 million in 2010. Universal, Sony, Warner, and EMI all have deals in place with the carrier -- probably one of the big reasons they've been able to amass so many subscribers, a number that currently stands around 450,000 spread across eight markets. Granted, compared to iTunes, half a million users still isn't much of a market driver -- but if nothing else, it seems to validate the business model, give carriers a big voice in the content distribution conversation, and serve as a testament to the fact that users are considering phones of all brands and platforms to be viable music players.