What do you do if you're a concert promoter staring at venues where two out of every five seats historically go unsold?

If you're Live Nation (NYSE: LYV), hooking up with flash sale giant Groupon to create a promotional hub may make sense to fill the empty seats.

GrouponLive should launch in a few weeks, and it's easy to see what each company will get out of the partnership.

Groupon's sales team has never had a problem rounding up eateries, spas, and gyms to fill its daily deal offerings, but it's been weak in live event marketing. It'll drum up half-priced admissions for the occasional stage production, food and wine festival, or orchestra performance, but it's been lacking access to the buzz-worthy concerts that thousands -- if not tens of thousands -- of locals will flock to on any given night. Since Live Nation also happens to own ticketing juggernaut Ticketmaster, Groupon realizes that it's better to play nice with Live Nation than to try and compete.

The stakes are even higher for Live Nation. Any price that it can get for an unsold seat is better than Nil City. Artists will also appreciate the opportunity to play before larger audiences to expand their fan bases.

There's also the viral mojo that Groupon is so good at cooking up. Someone snagging a deal through GrouponLive will likely be able to share that deal through Facebook, Twitter, and other social websites with a single click. Live Nation is way behind Groupon in this regard, even if it would be so simple to encourage ticket buyers to promote event attendance in exchange for future discounts.

Are we talking about half-priced last-minute tickets or full-priced admissions with some neat perks like area dining discounts, club passes, or artist-related freebies? This week's announcement doesn't provide all of the details, giving GrouponLive the flexibility to offer unique localized deals on an event-by-event basis.

It's a win-win move at a perfect time for the music industry. Warner Music Group's (NYSE: WMG) mired in red ink, but it just posted its first sequential gain in quarterly revenue in a year. Google (Nasdaq: GOOG) announced a new Web-based music service yesterday, hoping to get more Internet users excited about music again.

It's not perfect. The very existence of GrouponLive may dissuade the initial wave of full-priced ticket buyers. If it's not a hot ticket, waiting may pay off. Then again, the beauty of ticketing is that the early buyers get the best seats. Waiting for a deal may mean having to pack binoculars.

We'll know early on if this is working or training the avid concertgoer to devalue the live music experience at full price. It makes perfect sense on paper, but this won't fly if selling 40% of the unsold seats at half price turns into selling 60% of the unsold seats at even steeper markdowns because everybody's expecting the discounts.

Is GrouponLive a good idea? Share your thoughts in the comment box below.