VCs Flock to Online Marketing Inc. scored the year’s largest Series A round for a U.S.-based company when it recently raised $75 million. Highland Capital Partners and Oak Investment Partners co-led the deal, and were joined by Steamboat Ventures, the corporate venture arm of The Walt Disney Co.

Santa Barbara, Calif.-based FastClick was founded in 2000 with $400,000 in seed capital, but had never sought institutional funding until earlier this year. CEO Kurt Johnson says that the original plan was to raise $50 million that primarily would be used to provide liquidity for both angel investors and company founders. The additional $25 million resulted from intense investor interest, and will be used to make strategic acquisitions.

“It was a challenging process, because there were term sheets with higher valuations that we turned down,” Johnson says. “We felt that Highland, Oak and Steamboat were the best firms given their relevant experience in our space.”

That space is online marketing, which had been abandoned by most VCs after the Internet bubble burst. Four years after the collapse, however, many investors are returning to the fold.

One such VC is Bob Davis, the founder of online search engine Lycos Inc., who now works as a general partner with Highland Capital. Earlier this year, he led an investment in online search marketing company Quigo Inc. He currently sits on the FastClick board.

“The Internet is still the best marketing vehicle around,” Davis says. “FastClick has a network of 7,500 [online] publishers, because it’s a company that helps other companies get their message to customers.”

So far this year, VCs have invested more than $150 million in 14 Internet marketing companies, including FastClick. It’s a far cry from 2000, when investors pumped $1.4 billion into 146 online marketing companies, but this year’s activity is twice what the space received last year. Among the other companies in the space to have raised capital recently is Poindexter Systems Inc., a New York-based online marketing company, that announced an $8 million Series D in September from Blue Chip Venture Co. and other investors.

“We’re seeing a second wave of online ad companies that essentially bootstrapped themselves while funding wasn’t available,” says FastClick’s Johnson says “Now, though, we offer a great value proposition, and VCs recognize that.”