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 billboard specialist Lamar Advertising (Nasdaq: LAMR) fell as much as 11% in intraday trading after the company guided to weaker than expected second-quarter revenue.

So what: For as disappointing as the second-quarter projection was, first-quarter results showed some promise. Revenue rose 4.5% to $255.2 million, while Lamar's net loss narrowed from $0.27 a share to $0.14 a share.

Now what: Still, investors focused on the second-quarter number. Lamar management told investors to expect $296 million in second-quarter revenue, far from the $302.4 million Wall Street had been calling for. Score one for my Foolish colleague Sean Williams, otherwise known as TMFUltraLong. (He's taking questions all day today -- click here to get in on the fun.) He called for a downturn in February, and the stock is off more than 29% since. I see no reason to expect a turnaround anytime soon.

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

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. You can try any of our Foolish newsletter services free for 30 days.

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