Maybe those "Mac vs. PC" commercials are on to something: Did you know that Windows users are 20 percent more likely to want to read about religion than Mac users?

Or that people who use Windows are 11 percent less likely to be Pittsburgh Steelers fans?

That's what the Austin-based news Web site Thoof has found among its readers, without asking them a single question on these topics.

These "Thooftoids" aren't based on scientific study. But they are signs of how personalized the Web is becoming.

You may already be used to Amazon.com's shopping recommendations, which are partly based on your past purchases, or TiVo's viewing suggestions, which correlate to your TV habits. But Thoof.com, which launched in June, takes things a step further: It aims to feed content to its users in such a personalized way that some might swear the site can read their minds.

It's a lofty goal, but the technology guru behind it is founder Ian Clarke, a technologist who has studied artificial intelligence and the way complex patterns emerge from the behavior of groups. Every time you visit a Web site, your browser transmits information about you — what operating system you're using, which Web browser you're visiting with, even your geographic location.

Thoof uses that information to determine what stories you'll see. If you're on a Windows PC, it may show you stories other Windows users liked.

You may see more stories about Austin. And every story you click on (or ignore) will be recorded to build a better idea of what you want.

With Web readers used to quick gratification and infinite choices, getting readers content they want quickly is vital to competing for their incredibly shrinking attention spans, Clarke said

"On any content Web site, we need to figure out what people want and show it to them; we need to figure it out quickly," he said.

Affable and polite, the Irish transplant and startup veteran started the company in February after moving here from Los Angeles to tap the University of Texas' talent pool in engineering. Thoof, which currently has eight full-time employees and contractors, raised a million dollars in seed financing from Austin Ventures.

"We primarily funded Thoof because Ian Clarke is a very bright technologist with a great background around online communities, and he had a well-developed investment idea," said Tom Ball, a venture partner with Austin Ventures. "We were also very excited to get Ian to move to Austin from California."

The Mac vs. PC "Thooftoids," are based on a sample of about 43,000 Windows PCs and 7,000 Macs visiting the site and what stories those users read.

Those findings demonstrate Thoof's ability to spot patterns, Clarke said. "Something as simple as 'Do you use a Mac or PC?' — how much does that say about you?" he said. "What's here is really just the tip of the iceberg."

Thoof also looks for patterns based on the e-mail addresses people used to register at the site. Thoof says those who use Google's Gmail are 4 percent more likely to want to read about Hillary Clinton than people who use Yahoo Mail.

If it sounds a little creepy — maybe you don't want a Web site to know how likely you are to read about Britney Spears — Clarke believes most people will give up a little bit of privacy if they feel they're getting something in return.

"People use loyalty cards in grocery stores if it's cheaper," he said. He pointed to Google, which has easy access to its users' e-mails and documents, as a company that has done a good job building trust by not exploiting that information.

John Blossom, an analyst on publishing and content technologies, says the site will need to build up a large community of people to submit stories and provide recommendation data to truly work well.

"Automated guesswork can only go so far with a small base of users," said Blossom, president of Shore Communications Inc. "As often happens with content technology, good features do not necessarily make a good publishing product. It takes a lot of work to get good quality content and the 'Aha!' factor with audiences to grow significant audiences."

Clarke agrees that the more users the site has, the better it will get at predicting what a specific visitor wants to read.

Right now, information like the Mac vs. PC comparisons are "fun inferences," Clarke said, "not a representative sample of the population at large."

But with more users, the preferences it finds should be more accurate.

Blossom said Thoof's personalization features could be usefully incorporated into other Web sites, something Clarke said Thoof is already exploring, with Thoof's site serving as a showcase for its technology.

Clarke said page views grew 158 percent from August to September and are on track to grow 190 percent from September to October.

Clarke projects Thoof.com will receive about 750,000 page views this month. The company plans to introduce targeted advertising on the site.

ogallaga@statesman.com; 445-3672

Thoof founder Ian Clarke's Web history

Freenet: The Free Internet Project, which sought to bring a censorship-free Internet to countries like Saudi Arabia and China. Clarke started it in 1999; it continues today.

Uprizer.com: A peer-to-peer data company he co-founded in 2001.

Cematics LLC:Started by Clarke in 2002, the company created software for live video streaming and was later folded into Joost.com.

Revver.com:A user-generated video site Clarke co-founded in 2005 that sought to share advertising revenue with its video contributors.