Facebook plans to announce at a developer event Monday that it will open up user-contributed information to third-party developers, according to a report Sunday in The Wall Street Journal.

The move would allow developers to build applications and services that--with users' permission--access user videos, photos, notes, and comments. The move would be a significant change for the social-networking site, which had previously retained tight control over the site and how developers interact with it.

To allow developers to take advantage of the free feature, Facebook users would have to give the companies access to their data, and users' privacy settings would extend to new services built, according to the report.

Allowing developers to track shared data would be another salvo in its assault on micro-blogging site Twitter, which allows third-party developers to build applications and services on top of its service.

The move seems a continuation of APIs (application programming interfaces) Facebook launched in February that let developers access content and methods for sharing in Facebook apps including Status, Notes, Links, and Video.

Of course, all this hinges on persuading Facebook's 200 million users to share their personal data, a topic that ruffled some feathers in February. Facebook users threatened to revolt after the company announced changes to its terms of service that had meant that its license on user content--a longstanding but little-publicized claim to an "irrevocable, perpetual, non-exclusive, transferable, fully paid, worldwide license" for promotional efforts--would no longer expire if a member deleted his or her Facebook account.

But facing a rebellion from thousands of users and a possible federal complaint from the Electronic Privacy Information Center, the social-networking service returned to its previous terms.