Nielsen//NetRatings on Thursday announced that Apple's iTunes Web site and software now reaches 14% "of the active Internet universe," up 241% from the year-ago period. The company said that iTunes had 6.1 million unique visitors in December 2004 and 20.7 million unique visitors in December 2005.

The firm also revealed that users between 12 and 17 years old are twice as likely as average Internet users to visit the iTunes Web site and use the software. By a 54% to 46% margin, they're also more likely to be male.

In addition, Nielsen//NetRatings' research found that iTunes users are 2.2 times more likely than the average Internet user to own a Volkswagen car, with Audi and Subaru vehicles also popular, and their alcoholic beverage of choice is hard cider, followed by imported and domestic beer.

Looking at media usage, iTunes users are 3.3 times more likely to read Wired magazine, with Rolling Stone and FHM also popular choices. Cartoon Network was their favorite channel, followed by HBO and BBC America.

Jon Gibs, Nielsen//NetRatings' director of media analytics, said in a statement: "As networks begin to decide what types of programs to either produce or distribute through iTunes video, they should match the TV audiences' offline purchase and media consumption behavior with that of the iTunes users to maximize the success of video downloads."

Nielsen//NetRatings also looked at the top 10 Web sites by parent company, as well as the top 10 Web sites by brand, for December 2005. In the former category, Microsoft was number one with an audience of almost 112 million unique users, each of whom spent just over two hours on its Web sites, on average. Yahoo!, Time Warner, Google, eBay, InterActiveCorp., Amazon, News Corp. Online, RealNetworks and the New York Times Company rounded out the top 10.

In the latter category, Apple placed ninth with about 35 million unique users, each of whom spent just over an hour on its Web site. Yahoo! led that category with 103 million unique users, each of whom spent three hours and 17 minutes, on average, at its Web site. The rest of the top 10 were Microsoft, MSN, Google, AOL, eBay, Amazon, Real and MapQuest.