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 Internet marketing specialist ReachLocal (Nasdaq: RLOC) plunged as much as 17% in early trading Wednesday after its revenue forecasts disappointed investors.

So what: ReachLocal, which went public last year, said it sees first-quarter revenue of $83 million to $85 million, versus the average analyst estimate of $86 million. Additionally, the company is now forecasting full-year revenue of $380 million to $400 million, while Wall Street was expecting $407 million.

Now what: I wouldn't be so quick to pounce on this plunge. The stock has performed particularly well since its May IPO, but today's news has Mr. Market questioning if there's a little too much optimism built into the price. ReachLocal's growth prospects certainly remain enticing, but with rising costs and price-pressuring gorillas like Google and Microsoft to worry about, investors would do well to wait for a bigger pullback before jumping in.

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