After last week's confirmation of plans to make its developers' platform an open source project, Facebook this week followed through by releasing most of the code that runs its platform, including the most frequently used methods and tags.

"This release is just a first step in providing you a look into Facebook Platform, and we hope you'll help us [to] iterate and improve on it," wrote Facebook's Ami Vora, in a blog post celebrating the official launch of the new Facebook Open Platform.

Meanwhile, also for open source development in the social networking arena, Google last week unveiled a new OpenSocial API for guiding developers through the process of building and distributing interactive gadgets.

In Vora's blog post, she said the initial goal of Facebook's open source play is to help developers better understand the underlying platform and more easily create applications, "whether it's by running your own test servers, building tools, or optimizing your applications on this technology."

An Open Source Projects page on Facebook's Web site now details the Facebook Open Platform, a Facebook Firefox Toolbar extension, the Facebook Exporter for iPhoto plug-in, the Facebook Animsation library, the Thrift framework for cross-language services development, and several other open source projects. It also runs a forum for supporting developers.

Most of the code released this week is licensed under the Common Public Attribution License (CPAL), but some of it is licensed under the Mozilla Public License (MPL), according to Vora.

Last Wednesday, Facebook confirmed industry rumors of its open source plans in a e-mail sent to BetaNews.

"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," a spokesperson wrote in the e-mail. "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."