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.

Microsoft is leaving nothing to chance here. The Zune will be available in 30,000 stores nationwide — versus 10,000 for the iPod, Microsoft says. Zune commercials will run several times during each episode of popular TV shows, bearing the slogan “Welcome to the social.” (Either there’s a noun missing there, or they’re using “social” as a noun, as in “ice cream social.”)

The bigger problem, though, is the draconian copy protection on beamed music (though not photos). You can play a transmitted song only three times, all within three days. After that, it expires. You’re left with only a text tag that shows up on your PC so that — how convenient! — you can buy the song from Microsoft’s store.

Image The Zune comes in white, black or brown and it offers a bigger screen than the iPods. It goes on sale on Tuesday.

This copy protection is as strict as a 19th-century schoolmarm. Just playing half the song (or one minute, whichever comes first) counts as one “play.” You can never resend a song to the same friend. A beamed song can’t be passed along to a third person, either.

What’s really nuts is that the restrictions even stomp on your own musical creations. Microsoft’s literature suggests that if you have a struggling rock band, you could “put your demo recordings on your Zune” and “when you’re out in public, you can send the songs to your friends.” What it doesn’t say: “And then three days later, just when buzz about your band is beginning to build, your songs disappear from everyone’s Zunes, making you look like an idiot.”

Microsoft says that the wireless sharing is a new way to discover music. But you can’t shake the feeling that it’s all just a big plug for Microsoft’s music store. If it’s truly about the joy of music discovery, why doesn’t Microsoft let you buy your discoveries from any of the PlaysForSure stores?