"We've seen something like 500 businesses clone the exact idea of Groupon," said Mason. "Most of them end up being like a knockoff, you know a Groupon knockoff is a lot like a Gucci knockoff or an i-pod knockoff. It's not the same as the original."
Groupon may be riding high now. But there are many tombstones for dotcom hot properties past, such as Pets.com, eToys.com and Netscape, once promising Internet companies that grew fast and flamed out.
"[I] take it with a grain of salt," said Mason. We're kind of like the 'N Sync of websites, where we might have some record, but we're not better than the Beatles. It's more of an artifact of the times in which we live."
Unlike so many dotcom wonders, Groupon is already turning a profit.
Watch the full story tonight on 'Nightline' at 11:35 ET