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 online media company SINA (Nasdaq: SINA) fell 10% today on concerns that the company's earnings will be worse than expected.

So what: E-Commerce China Dangdang (NYSE: DANG) is driving Chinese Internet stocks lower today after the company reported weak second-quarter earnings. SINA reports earnings Wednesday after the market closes, and there's concern the company will follow in Dangdang's footsteps.

Now what: We'll have to wait another day to hear exactly what SINA has to say, but the market will likely have a strong response for this volatile stock. Short interest has ballooned to more than 10% of SINA's float, and they'll either be proven right or be headed for the hills after earnings. With volatility very high right now, I would wait this out until after earnings when SINA should give us a clue whether its business is impressive or disappointing to investors.

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

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.