Facebook is releasing as open-source software parts of its application development platform in order to make it easier for programmers to create applications for the social-networking site, the company announced Monday.
Facebook will offer as open source "most" of the code that runs its platform, plus implementations of its most popular methods and tags.
This is another step in Facebook's program for external developers, which it kicked off a little over a year ago when it opened up its platform to them. Since then, about 400,000 developers have created some 24,000 applications for Facebook.
With this move, Facebook is also responding to Google's OpenSocial, an initiative to establish a standard set of common APIs (application programming interfaces) that will let developers create social-networking applications that can run with minor modifications in multiple sites.
OpenSocial is generally considered a challenge to Facebook's platform, because observers believe it could make it easier for social-networking sites to match Facebook's broad catalog of third-party applications.
Among OpenSocial's supporters are Yahoo, AOL and MySpace, Facebook's biggest competitor. In March, Yahoo, Google and MySpace formed a nonprofit foundation to promote the OpenSocial platform as a neutral, community-governed specification.
With the open-source portions of its code, Facebook expects that developers will find it easier to test and tune their applications, and create their own tools, among other things.
The Facebook Open Platform, or fbOpen, as the open-source portion of the platform is called, can be extended so developers can create their own tags and API methods, Facebook said.
The open-source portion of the platform includes the REST API, FBML parser, FQL parser, and FBJS sanitizer and proxy, Facebook said.
Most of the open-source code is being made available via the Common Public Attribution License (CPAL), while the FBML parser is governed by the Mozilla Public License (MPL).
Gartner analyst Ray Valdes calls fbOpen a good move that became necessary for Facebook to make in light of the OpenSocial challenge.
"OpenSocial is gaining enough ground and becoming more real, whereas in the past it was basically a bunch of people talking about the specification. That spec is now being implemented and deployed," Valdes said.
In addition, OpenSocial wasn't significantly open sourced, but that also has evolved to the point where it is now a real part of the open-source portfolio for social-networking applications, he said.
On a broader scale, Facebook is also reacting to the overall trend for greater interoperability, away from "walled garden" sites and embracing the open Web and data portability, Valdes said.
"Facebook needed to respond and they did. Whether what it's doing is sufficient depends on the uptake among developers and partners," Valdes said.
In addition, a possible long-term benefit for Facebook is that this open-source effort may attract more sophisticated developers who are able to create more substantial applications than the typically lightweight widget-like Facebook applications, Valdes said. In particular, Facebook could benefit from developers who create enterprise applications for specific vertical industries, he said.