So, the first quarter was a good one. Shares of Priceline rose nearly 3.8% on decent volume by the close of Monday's session. Obviously, the market liked what it saw.

One thing investors have to be careful about is management's commentary on guidance. If you read that section of the earnings release, you'll note that the company isn't too certain what the near-term future will bring. There's a cautious tone to the message. Clearly, that caution has to do with the recession.

But when you look at the way the markets have been acting, and when you consider the company's numbers, you have to wonder if everything's going to turn out all right. Heck, just look at Priceline's stock itself. Take a look at how it's performed over several time periods. At the time of this writing, shares have nearly doubled over the six-month frame. That's incredible. The stock closed at over $108 per share on Monday. Know what the 52-week low was back near the end of October 2008? Try around $45 per share. If you had conviction back then, you made money.

Okay, Priceline apparently is doing well. The market loves the stock. And that's what concerns me. You may want to wait for a pullback. Did I say may? Well, truth be told, I think Priceline could be going higher from here. Everyone is just so bullish right now. But let's be realistic. It's better to buy lower than higher. And Priceline is definitely higher than lower. In the end, you can make your own decision, but I would be very cautious about going all-in at this juncture.

Disclosure: I don't own any company mentioned; positions can change without notice.