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 real-estate-listing service Trulia (NYSE: TRLA) skyrocketed 25% today after the company's quarterly results and outlook topped Wall Street expectations.

So what: Although Trulia remains in the red with a Q2 loss of $0.07 per share, whopping top-line growth of 77%, coupled with upbeat guidance for the current quarter, reinforces analyst optimism over the housing market and mobile trends working in its favor. In fact, close rival Zillow, which is scheduled to report on Tuesday, is also rallying on the report as investors speculate on similarly strong results.

Now what: For the third quarter, management now sees revenue of $30.5 million to $31.5 million, representing 65% to 70% year-over-year growth, versus Wall Street's estimate of $29 million. "We are now well positioned to be the leader in our sector and to further penetrate the enormous market opportunity that lies before us and drive incremental opportunities to grow revenues," said CEO Pete Flint in a conference call with analysts. Of course, with the stock now up more than 200% from its 52-week lows and trading at a 60-plus forward P/E, I'd wait for some of the exuberance to fade before buying into that bullishness.