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 photo service Shutterfly (NASDAQ:SFLY) soared 19% today after its quarterly results and outlook topped Wall Street expectations.

So what: The stock has been clobbered over the past couple of years on fears that free social networking sites such as Facebook (NASDAQ:FB) were making its services obsolete, but today's fourth-quarter results -- EPS of $1.40 on revenue of $351.8 million versus the consensus of $1.01 and $309.7 million -- and upbeat outlook helps ease those concerns. In fact, the vast majority of Shutterfly's customer additions in the quarter were driven by new integrated marketing campaigns, as opposed to acquisitions, giving investors plenty of optimism over organic growth going forward.

Now what: Management now expects 2013 EPS of $0.39-$0.42 on revenue of $739 million-$746 million, versus Wall Street's view of $0.46 and $707.8 million. "Our singular focus on addressing the ever increasing challenges that consumers face as they try to do more with their photos and memories has enabled Shutterfly to emerge as the market leader," CEO Jeffrey Housenbold said. "We remain confident in our strategy and in the early and large markets in which we operate." With the stock now up nearly 50% over just the past three months and trading at an 80-plus forward P/E, I'd wait for some of the exuberance to fade before buying into that bull talk.

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