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 health website operator WebMD (NASDAQ:WBMD) soared a whopping 25% today after its quarterly results and guidance topped Wall Street expectations.

So what: The stock was crushed in 2012 as weak ad spending and increased competition pressured results, but a wide fourth-quarter revenue beat -- $132.7 million versus the consensus of $124.1 million -- coupled with positive full-year guidance suggests that things are turning. In fact, total traffic to its websites rose 20%, while unique users per month surged 28%, giving Wall Street plenty of good vibes over its growth prospects going forward.

Now what: For 2013, management now sees a loss of $0.13-$0.45 per share on revenue of $430 million-$455 million, well ahead of the consensus loss of $0.44 per share and a top line of $422 million. "We enter 2013 as a more nimble organization that is well positioned to meet the needs of our users and clients in a dynamic and demanding marketplace," said CEO Cavan Redmond. But while its short-term prospects are certainly looking better, WebMD's still-shaky competitive position continues to make the stock a questionable long-term opportunity.

Interested in more info on WebMD? Add it to your watchlist.

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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.