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 real estate information specialist Zillow (Nasdaq: Z) have zoomed up by north of 18% after the company reported strong first-quarter earnings.

So what: Revenue more than doubled to $22.8 million, the sixth consecutive quarter of triple-digit growth. The company posted net income of $1.7 million, or $0.06 per share, compared to a net loss of $0.06 per share a year ago.

Now what: Guidance also looked strong, with second quarter sales expected in the range of $25.5 million-$26.5 million, while the Street would have been happy with just $24.8 million. Average monthly unique users jumped 84% to 31.8 million, and Zillow users now look at homes on mobile devices more than they use its namesake site. Following up the results, Benchmark is reiterating its "buy" rating while boosting its price target to $44.

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Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of Zillow. Motley Fool newsletter services have recommended buying shares of Zillow. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.