With the wounds of its latest upgrade still fresh, popular social network Facebook.com is set to make an even more sweeping change: opening its doors to the masses.

At first, Facebook.com was the exclusive domain of college students. More recently, it began admitting high school students and employees of certain selected companies. Beginning next week, though, AdAge reports that "people will be able to join through roughly 500 regional networks, a number that Facebook expects to grow with time." In short, anyone who lives somewhere, or says they live somewhere, will be able to join.

Paidcontent.org, which says the strategy change may be necessary, is among the many to point out that the jittery Facebook membership may not take to the new strategy: "The move takes Facebook a step closer to MySpace's open frontier - something that isn't likely to thrill those who see Facebook as an antidote to the massive News Corp. social network." Indeed, it was the fear of another cool reception that prompted Facebook to delay the launch of "open registration" from this week to next. "We are going to think through how to better inform users, and we don't want to risk expanded registration being a big issue on the heels of last week's changes," spokesperson Marlene Deitch said.

Doubters and turbulence aside, the expansion plan makes sense to The Browser, who had a chance to discuss it with CEO Adam Zuckerberg a few weeks back. Zuckerberg likes to describe his site not as a media property but rather a utility more akin to e-mail: a tool that allows users to keep track, for example, of friends' phone numbers and addresses. (Anyone remember PlanetAll?) It's a smart way to distinguish the Facebook approach from the occassionally vague-and-bloated-seeming "media" mission of market leader MySpace. A utility requires scale, so by expanding its domain, Facebook may actually prove of more enduring use to its existing members and a bigger threat to its rivals.

This assumes, of course, that it solves the thorny problem of giving sufficient control to members over how they share their personal information - and that the brash Zuckerberg manages not to alienate his membership along the way.