It's not just stateside group-buying sites that have fallen out of favor. China's Vipshop (NYSE:VIPS), the dot-com speedster offering flash-sale deals on brand-name apparel and related accessories, was one of last week's biggest losers after warning that it will fall short in its most recent quarter. 

Vipshop stock plunged 36% on the week, hitting a fresh 52-week low in the process after revising its initial top-line guidance. It now expects to report net revenue that's the U.S. equivalent of between $1.35 billion and $1.37 billion when it reports third-quarter results tomorrow afternoon. That's a healthy 61% to 63% ahead of what it posted a year earlier -- stateside leader Groupon (NASDAQ:GRPN) would kill for that kind of growth -- but Vipshop was forecasting net revenue to soar by 71% to 74% for the quarter just three months earlier.

A stock doesn't remain a market darling if it hoses down its own outlook, and that will probably mark the end of one of the more enviable streaks among growth stocks. Vipshop stock more than doubled every year since going public at a split-adjusted price of $0.65 a share in early 2012. The shares rose 174% in 2012, soared 370% in 2013, and more than doubled last year on the way to a 133% pop. Things were going so well that Vipshop executed a 10-for-1 stock split last November to get its stock price back into the double digits. 

Vipshop shares were trading slightly higher this year heading into last week, but the stock now finds itself in a 30% hole for 2015. Vipshop had been a consistent winner in the otherwise volatile realm of Chinese growth stocks until proving mortal this year. Vipshop has also bucked the trend against flash sale sites worldwide. Niche leader Groupon went public just three months before Vipshop, and its stock has surrendered 87% of its value. 

It's true that Groupon and Vipshop have different models. Groupon made its mark by offering markdowns on local experiences. Groupon, LivingSocial, and other U.S. sites became hot hubs for restaurants, spa operators, and other service providers to drum up new leads by selling pre-paid vouchers through the site. The model has floundered, and even the mighty Amazon.com announced that it will bow out of the market when it shutters Amazon Local next month.

Vipshop has never tried to sell the invisible. It offers physical products, something Groupon has been trying to get off the ground in recent years with Groupon Goods. 

Don't let last week's plunge dissuade you if you're a Vipshop investor. Growing at a better than 60% clip is not the mark of a laggard, and we're talking about a stock that's trading at just 16 times next year's forecast. Selling retailer brands at significant markdowns has been a good place to be as China's economy slows, and that will continue to be a good place for Vipshop -- and its investors -- to be.

Rick Munarriz has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Amazon.com. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.