Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of South American online auction operator MercadoLibre (Nasdaq: MELI) sank 12% on Wednesday after its quarterly results disappointed Wall Street.

So what: While MercadoLibre's first-quarter miss wasn't all that bad (EPS of $0.45 on revenue of $83.7 million versus the consensus of $0.45 and $84.3 million), investors seem worried that it's a sign of even bigger disappointments down the road. The company continues to grow nicely, but today's results suggest that it isn't growing fast enough to justify its particularly lofty P/E.  

Now what: Long-term-growth seekers should look into this plunge as a possible entry point. "I look forward to the rest of 2012, as we keep driving innovation on top of the success of our current initiatives, with the goal of delivering sustained top and bottom line growth during 2012," said CEO Marcos Galperin. Investors often do well by pouncing on short-term hiccups from potent global growth stories, and today's drop might be providing that opportunity.

Interested in more info on MercadoLibre? Add it to your watchlist.