Accenture, the technology consulting and services group, is making a real bet on the Web marketing business.

The firm says that technology is finally getting good enough to deliver Web display ads tailored to consumers’ demographics and interests. And big companies, it says, are eager to shift more of their ad spending onto the Web.

Last month, the new Accenture Interactive unit announced that it would handling the technology and services on Procter & Gamble’s consumer Web sites.

And on Tuesday, the firm said that it is forming a partnership with a closely watched Silicon Valley startup, Adchemy. As part of the agreement, Accenture will be one of three investors in a $31 million funding round for Adchemy, joining the Mayfield Fund and August Capital. The venture firms were investors in earlier rounds, which raised $27 million.

Adchemy, based in Redwood Shores, Calif., is one of several ambitious young companies trying to employ cutting-edge computing techniques — including machine learning, statistical inference and advanced data mining — to Web advertising.

By all accounts, Adchemy has put together a first-string team of experts in those disciplines with both impressive academic credentials and experience at companies like eBay, Friendster and Capital One. One of the people who advised and worked on Adchemy’s technology was Rajeev Motwani, a computer science professor at Stanford, who was one of the co-authors on the early paper that described the idea that became Google’s technical touchstone, the PageRank algorithm. (Mr. Motwani died tragically in June in drowning accident.)

The ideal, according to Matthew Symons, Accenture’s managing director for digital marketing optimization, is to use Adchemy’s technology and other tools to not only figure out the sort of person who is visiting a site, but to then deliver to the visitor a Web experience that is appealing and increases the chances of converting that person into a buyer.

“The commercial Web has been a brochure-ware experience up to now,” Mr. Symons said. “What you want is digital assets that can be assembled on the fly, depending on who is viewing a site.”

Mr. Symons points to a recent survey by Forrester Research that projected online advertising, now 12 percent of total ad spending, would rise to 21 percent in five years. “If they are going to spend that kind of money,” he noted, “they are going to need this kind of capability.”

Murthy Nukala, the chief executive of Adchemy, calls his company’s technology “statistical personalization.” It doesn’t really identify a person, he said. But by probing vast data sets, from click streams to marketing information from firms like Acxiom, Adchemy can identify the sorts of people -– by age, gender and interests -– that advertisers want to pinpoint.

“We don’t hold any data. We just connect to 30 or 40 data sources,” Mr. Murthy said.

Despite Mr. Murthy’s assurances, the technology raises all sorts of privacy questions. But this kind of targeted marketing is becoming the way of the Web, and Accenture wants to get into the game.

[nytbits]