Do you remember Flooz.com? Like lots of websites spawned in the late ’90s, it aimed big and spent bigger. “Flooz” was a virtual currency you could use at any retailer who’d accept it, but the company squandered lots of real currency in the process—at least $35 million—before going bankrupt in 2001, after 19 months. In a world of web winners and losers, it merited its own notorious category: a “floozer,” you might say.

Today, a flameout like Flooz would be unlikely to replicate in the fast-expanding world of lean startup. While the name reeks of business jargon and even sounds misleading, lean startup groups have been magnets for 21st Century tech pioneers—though the philosophy is not without its critics. Some web pundits, such as U.K. startup funding blogger Nick Pelling, say that the lean startup ethos of testing a business idea on a consumer base before deciding to develop them “lacks

cojones, or ‘bravery’ if you wish.”

Still, the exploding numbers indicate lean startup has arrived, and to stay. The Chicago Lean Startup Circle has seen membership explode by a staggering 1800 percent in three years, to 2,800 plus people. There’s been similar growth in Los Angeles (where the local lean startup circle has grown to 2,868 since its founding in 2010) and San Francisco (with 3,581 members since its founding in 2009).

Todd Wyder, co-executive director Chicago Lean Startup Circle, says the ideology gets would-be web moguls to test businesses in low-risk scenarios, and proceed only if consumers approve or suggest changes that steer them in the right direction. It also saves you lots of cash and heartbreak, says Wyder, recalling a recent thank-you note from a digital entrepreneur who hadn’t quite stumbled on the next Google. Yet thanks to lean startup, it didn’t turn into the next Flooz, either.

“It turned out his idea had no merit,” Wyder says. “But he told me that without lean startup, he would’ve cashed in his entire 401(k).”