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What: Shares of Chinese online game developer Changyou.com (Nasdaq: CYOU) have plunged today by as much as 14% after the company reported fourth-quarter earnings.

So what: Even though the results topped estimates, guidance has spooked investors. Revenue added up to $137.7 million while earnings per share was $1.33. Compare those to the market's expectations of $124.1 million in sales and a $1.09 per share profit.

Now what: Although first-quarter revenue is forecast to be better than expected at $130 million to $134 million, the bottom-line guidance left a little to be desired. Next quarter's profit is forecast to be below the consensus estimate of $1.13 per share, with the company is expecting anywhere from $1.08 to $1.12. Majority owner Sohu.com (Nasdaq: SOHU) also reported today, and both companies' shares are getting slammed today after one-time impairment charges weighed on results.

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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. Motley Fool newsletter services have recommended buying shares of Sohu.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.