As expected, the much-discussed Google social play turns out to be an alliance with other companies to "open up" social networks and their data to developers. TechCrunch and the New York Times both have early news of an expected announcement tomorrow on how Google, along with partners like Ning, Linked In, Friendster, and others, will introduce a set of common APIs — called OpenSocial — to be used for getting data from and writing applications for social networks.

The idea, as the New York Times explains, is to help combat the number of people who are developing for Facebook and not thinking of other social "platforms." Says the NYT:

"It is going to forestall Facebook’s ability to get everyone writing just for Facebook,” said a person with knowledge of the plans who asked to remain anonymous because he was not authorized to speak on behalf of the alliance. The group’s platform, which is called OpenSocial, is "compatible across all the companies," that person said.

Google has already been trying to do this on its own — promote itself as a development platform — as our Google Gadget Ventures: Get Paid To Develop Google Gadgets post from last June explains. But enlisting others will help Google make Facebook seem closed and on the defensive.

As I explained in the Google To Pressure Facebook To "Free" Social Data & Planning Google Earth World? post from September:

At a time when some worry that Facebook is too closed, the Google rumors make a lot of sense — that by pushing out whatever social information it has now, Google can make a play that all social networks should spill their data, thus robbing Facebook of its most important asset. But as I said in my TechCrunch comments, that type of push will haunt Google when you’ve got search developers asking why it doesn’t open up its massive search index.

That September post also revisits some of the recent changes Google has been doing to Orkut to try and make it more attractive.

TechCrunch reports that "OpenSocial" will have more information posted here tomorrow and will be:

A set of three common APIs, defined by Google with input from partners, that allow developers to access core functions and information at social networks:

• Profile Information (user data)
• Friends Information (social graph)
• Activities (things that happen, News Feed type stuff)

Hosts agree to accept the API calls and return appropriate data. Google won’t try to provide universal API coverage for special use cases, instead focusing on the most common uses. Specialized functions/data can be accessed from the hosts directly via their own APIs

John Battelle has what looks to be a draft press release here. Much discussion is starting on Techmeme.

Postscript: Google’s sent me the following summary information about the launch:

OpenSocial is a set of common APIs for building social applications on the web.

Common APIs mean that developers only have to learn once in order to start building social applications for multiple websites, and any website will be able to implement OpenSocial and host social applications. OpenSocial will bring more powerful and pervasive social capabilities to the web because developers will be able to develop and distribute their applications more easily. Users will be able to enjoy new social features faster and in more of the websites, web applications, and social networks they use.

Benefits for Developers:

• A new, broad distribution network for developers – i.e., all OpenSocial-enabled websites
• Learn once, write anywhere
• Standards-based – HTML and JavaScript

Benefits for Web sites:

• Faster development – more features, more quickly
• Can engage a much larger pool of third party developers than they could without a standard set of APIs
• Can devote their resources to strategic projects rather than extensive API and developer support

Selected Partners

• hi5: Ramu Yalamanchi, Founder and CEO
• LinkedIn: Adam Nash, Director of Product
• Ning: Marc Andreesen, Co-founder
• iLike: Ali Partovi, CEO
• Slide: Max Levchin, founder and CEO

Related Topics: Google: OpenSocial | Google: Orkut

About The Author: Danny Sullivan is editor-in-chief of Search Engine Land. He’s a widely cited authority on search engines and search marketing issues who has covered the space since 1996. Danny also oversees Search Engine Land’s SMX: Search Marketing Expo conference series. He maintains a personal blog called Daggle (and maintains his disclosures page there). He can be found on Facebook, Google + and microblogs on Twitter as @dannysullivan. See more articles by Danny Sullivan