It’s the most fashionable acquisition of the week. Apple (News – Alert), after all, is a very fashionable company.

CNet is reporting today that Apple has purchased a San Francisco-based creative consulting company that specializes in Web applications and marketing projects using HTML5. Apple is using HTML5 increasingly on its product pages, iAd advertising, and on iCloud.com, which may help explain the acquisition.

So why is the acquisition so fashionable? Particle was founded in 2008 with help from a set of investors. One of them was boy singer/actor Justin Timberlake. It’s said that Apple targeted Particle primarily for its talented personnel.

“Particle is a growing professional services business in creative concept work, visual and user experience design, and technical implementation,” according to Particle officials. “Its founders have a significant history with digital creative consultancy. “

Particle has worked in the past with not only Apple, but also Google, Disney, Sony, Ericsson, Motorola (News – Alert) and others. The company launched short social video service Robo.to and has also created some "labs" projects including Intervue.me, an asynchronous video interviewing project.

The purchase price is being kept secret, and Apple has yet to comment on the acquisition.

Prior to the acquisition, Particle had only about a dozen employees, not all of whom are sticking around to become Apple employees, reported CNet. Several of Particle’s existing employees previously worked with Yahoo as part of its user experience design group.

Particle founder and chief technology officer Aubrey Anderson also consulted for Apple between 2006 and 2008.