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 DealerTrack (Nasdaq: TRAK) have been derailed today, down by as much as 12%, after the company reported earnings last night.

So what: Revenue in the fourth quarter jumped 47% to $91.3 million, with adjusted net income coming out to $10.3 million, or $0.24 per share. Both figures handily topped the Street's expectations of $84.6 million in sales and a $0.20-per-share profit.

Now what: CEO Mark O'Neil attributed the strong results to healthy auto credit and car sales trends throughout the year. What's really weighing on investors is the company's guidance for the coming year. DealerTrack expects fiscal 2012 to see revenue between $365 million and $372 million, with adjusted net income between $44 million and $47 million, or $0.99 per share to $1.06 per share. Both forecasts fall short compared to what the market was looking for.

Interested in more info on DealerTrack? Add it to your watchlist by clicking here.