In the annals of my investment boo-boos, near the top of the list is a shortsighted dumping of stock in a profitable online marketing service. What was I thinking? "Come on, they're just doing click-through ads. How much can that be worth?" Duh.

Web advertising golden child ValueClick (NASDAQ:VCLK) -- the competitor of my lost investment in (NASDAQ:FWHT) -- has pounded expectations for the past several quarters, stinging even savvier investors suffering from momentary crises of faith.

Today's awesome Q4 and full-year 2003 results shot ValueClick up 5% into the $12 turf, a 52-week high. Fourth-quarter revenues were up 61% over last year, fueling earnings of $0.07 per share, a nice 250% increase. For the year, revenues climbed 48% to $92.5 million. Those results include revenue jumps from smart acquisitions, leading the bigger, meaner ValueClick to full-year earnings of $0.13 per share. That's a lot better than last year's $0.14 loss.

Great results, but is there any value left in this click for investors? That depends on what your definition of value is. V-to-the-C has had a spectacular run-up, a four-bagger today, from around three bucks a stub at this time last year. For 2004, the company issued guidance of $145 million to $148 million in revenue, and earnings from $0.21 to $0.27 per share.

If we split the middle on those numbers, ValueClick trades at 50 times estimates. That's doesn't seem crazy considering the near 100% growth baked into the math above, but it makes it pricier than competitor DoubleClick (NASDAQ:DCLK), which trades around 28 times forward estimates.

I wouldn't count anyone out of this game. Web advertising is booming, and there seems to be plenty of room on the Net for smaller outfits. Even gorillas like Yahoo! (NASDAQ:YHOO) and privately held Google haven't been able to muscle competitors off their turf.

Wondering how to take advantage of the brave new Web world? Find out in the Fool's Help with this STUPID Computer discussion board.

Photojournalist Seth Jayson fell down a rabbit hole and ended up contributing to the Fool, which is investors writing for investors. He has no stake in any firm mentioned above.