How do you know when you’ve come up with a good idea? When Pearl Jam comes up with the same exact one.  The band that testified against Ticketmaster, toured with Neil Young, and taught us how to Rock the Vote, is now giving away their music for—well, not a song, but a tweet.

To promote their new album, Backspacer, they’re asking fans to talk about their new song “Just Breathe” on Twitter. In exchange for the tweet, fans will receive a code which allows them to download a live version of the song from iTunes for free.

Sound familiar?

Those of you who follow the goings on in the Vertiyoverse will know about a little product we created months ago called TweetPromoBuilder.com. On our site, anyone with a free offer to promote—be it a discount code or a download—can set up a twitter ad asking customers to send a tweet in exchange for the giveaway.

And speaking of followers, Pearl Jam’s free song isn’t completely without its strings. By sending the tweet on the site set up specifically for the band’s Twitter promotion, the Pearl Jam twitter feed will automatically be added to the list of those that you follow. TweetPromoBuilder.com offers that as an option, allowing users to forgo it.

Is this what the future holds for us marketers? Is promotion going to become one big online popularity contest where consumers can use their status as currency and hock it for wares? If so, then may the smartest kids win.