Joe from Flixter denotes why this is SO HUGE: his app will run anywhere that the OpenSocial platform is running. Plaxo. Ning. NewsGator. MySpace. No rewriting of apps.

The Open Social announcement is an equivalent to Sun announcing Java in the mid-nineties… The big promise back then was write-once run-everywhere… Java never became the major success for writing end-user apps that Sun had dreamed off, so the jury has to be out. Hopefully the Open Social API designers will keep Java’s history in mind as they take their technology forward.

MS Windows users don’t care whether Mac users can run AutoCAD. Similarly Bebo users won’t give a damn whether or not Facebook or Ning users can run Flixster…. unless Bebo users can share the Flixtser data, their movie reviews, with their friends on other sites.

Great news for developers, but no news for users of these sites.Robert Scoble is raving about it something rotten on twitter and his blog, like a surfer riding the big kahuna… I love his excitement but I can’t share it.

End users now get the same “virus apps” spreading across multiple social sites (MySpace, Ning, Hi5, etc) because these apps are can now be built atop the same APIs. The problem is the data remains stuck within the “container”, i.e. the social network site and cannot cross the boundary to another site. For example, the developers of Flixster can now write a single app for all social network sites using the Open Social APIs, however I couldn’t share my Flixster data on Hi5 with my some of my friends on Bebo, eventhough the same app would be available.

Marshall Kirkpatrick hits the nail on the head by saying that Open Social should really be called Open Widget, as it more aptly defines the problem it trying to solve.

Open Social helps developers write apps for multiple platforms. Open Social does nothing to help users connect across multiple platforms.