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 social networker Facebook (Nasdaq: FB) have fallen by as much as 17% today to hit new lows after the company reported second-quarter earnings.

So what: Total revenue rose to $1.18 billion, which resulted in a GAAP net loss of $157 million, or $0.08 per share. Most of this was due to stock-based compensation expenses related to the IPO, and on an adjusted basis, Facebook posted a non-GAAP profit of $0.12.

Now what: The company has now reached a total of 955 million monthly active users, with growth international user additions. Ad revenue was $992 million, and payments revenue was $192 million. Worldwide average revenue per user increased to $1.28, slightly better than a year ago. Investors were a bit nervous about the lack of financial guidance for the coming quarter or the full year and continue to question whether Facebook is worth its lofty valuation.

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