Call it the Groupon evolution or revolution, but one thing is certain: The new retail frontier isn’t online, but a web-influenced offline. “Group-deal sites aggregate demand,” says Kurt Peters, host to this San Diego conference. “It’s a way to attract customers to local retailers.” With the number of daily-deal offers expected to spike 138% in 2011, online behemoths like eBay are trying to keep up by furiously expanding. In 2010, the retailer upped its offerings from 35 million listings to 100 million and burst onto the mobile scene with not one, but nine free apps. Sounds like a deal, but where’s our 60% off?