Advertising on the Web could top $9 billion this year — and there are lots of ways investors can profit from the trend.

Sooner or later, advertisers had to figure out the Internet. Here was a medium that was reaching into nearly every office in America. And at home, it was wresting millions of eyes away from the TV. It could even count mouse clicks. Today, Net advertisers are finally hitting their stride.

It started with advertising on search engines, such as Google Inc., which collectively grew in five years from near zero to a $3.9 billion chunk of the online ad industry. Now companies are rushing to promote their brands with ever more banner ads, skyscrapers that crawl up the pages, and full-motion videos. Internet advertising should reach $9.4 billion in 2004, according to Kagan Research LLC. And with continued double-digit growth, it’s on pace to surpass magazine advertising in about two years, adds Kagan.

Right now, excitement about online advertising is behind a wave of industry consolidation. AOL dished out $435 million for in June. In mid-November, Dow Jones & Co. (DJ ) agreed to buy CBS Marketwatch for $515 million, a rich 30 times next year’s estimated cash flow. Analysts believe that Dow Jones, whose is available to subscribers only, is looking to tap the bounty of advertising that a free site can attract because it draws more visitors than paid-for competitors. The current fever has a hint of the dot-com craze, but there’s one vital difference: While the advertising stars are still spinning bold visions of the online future, they’re measuring their progress with profits every step of the way.

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