A Facebook spokesperson this afternoon confirmed rumors circulating all day long that the social networking site will turn its year-old developers' platform into an open source project.

Following on the heels of an announcement last week that Facebook is opening a new developers' sandbox, rumors of the impending open source initiative were first published late last night by blogger Michael Arrington in TechCrunch.

In response to an inquiry from BetaNews, a Facebook spokesperson sent a written response by e-mail late this afternoon.

"We're working on an open source initiative that is meant to help application developers better understand Facebook Platform and more easily build applications, whether it's by running their own test servers, building tools, or optimizing their applications," according to the Facebook spokesperson.

"As Facebook Platform continues to mature, open-sourcing the infrastructure behind it is a natural step so developers can build richer social applications and share what they've learned with the ecosystem. Additional details will be released soon."

Ri Pierce-Grove, an analyst at DataMonitor, told BetaNews this afternoon that Facebook's newly revealed plans for an open source initiative "represent Facebook's realization that its strength is in its development community as much as in its code."

The Facebook spokesperson didn't comment, though, on another question posed by BetaNews, about the relationship between Facebook's open source initiative and the sandbox announced last week as a way to familiarize developers with a new user profile design for the Facebook Platform -- now in progress for months, and delayed once already last month.

Meanwhile, also last week, Google unveiled a new OpenSocial API sandbox for guiding developers through the process of building and distributing interactive gadgets.

"The major social networks are competing for the attention of the developer community, as the moves by Facebook and Google clearly show," Pierce-Grove told BetaNews today.

Although Facebook has kept publicly silent about the open source initiative until today, the social network has been much more forthcoming about its plans for a new user profile for the Facebook Platform.

In a blog on the Facebook site, Facebook's Pete Bratach has been telling developers that the new profiles are now scheduled to launch in June.

In video provided to journalists today from a small "outdoor press event" last week, Facebook's Mark Slee said that the new user profiles are aimed at providing new "integration points" for third-party application developers, while also giving better profile control and ease of use to social networks. Developers will be able to create "custom tabs" for the tab-based UI, for example, he said.

But the Facebook developers made no specific mention -- in the video provided from last week's event -- of open sourcing.