The Zune, Microsoft's answer to the iPod, has built-in wireless, a feature often dreamed of for the iPod. However, for now, Zune's wireless can only be used to share music with other Zunes. David Pogue sums up this problem perfectly:
Microsoft also faces what’s known as the Dilemma of the First Guy With a Telephone: Who you gonna call? The Zune will have to rack up some truly amazing sales before it’s easy to find sharing partners. Source
As if that wasn't bad enough, Microsoft has further crippled this feature by imposing Draconian playback limitations on songs transferred from Zune to Zune; the song is only good for 3 days or 3 plays (which ever comes first). Maybe if the limit were more like 10 days or plays, the restriction wouldn't be hopelessly frustrating. But what's really so surprising about Zune's wireless, is that it could be used for a number of other things that would not suffer from the "First Guy With a Telephone" dilemma. For instance, purchasing music over the internet, sharing music over the web, internet radio, wireless syncing, wireless connectivity to the XBOX 360, or wirelessly connecting to speakers.