One way to make yourself accessible to others is by offering a valuable service that they can't easily turn down. Microsoft hopes it's doing that today by offering users of LinkedIn, Facebook, and three other platforms a way to consolidate their contacts...through Windows Live.

Rarely does a week go by without Microsoft announcing another interoperability initiative; the company has put forth two new ones just this morning. One deals not so much with making some Microsoft product accessible to the outside world as it does with offering a kind of bridge between social media platforms, although it's hard to escape noticing that this bridge runs right through Windows Live Messenger.

The concept is called the Windows Live Contacts API, version 1.0 of which entered a public beta process this morning. The new API is being described as a way for Facebook, Bebo, LinkedIn, Hi5, and Tagged social networks -- the first five partners in this operation -- to exchange user identity data through the Windows Live platform.

This morning, Windows Live Platform Director John Richards described this beta as "a safe, secure two-way street for users to move their relationships between our respective services."

The move comes as a benefit of Microsoft's investment in Facebook last October, which at the time was seen as a move that could help consolidate the presence of Microsoft's advertising platform on Facebook properties.

The first test of this platform-bridging concept comes in the form of a user ID transfer page inviting consumers to invite members of these five social networks to join Windows Live Messenger. The purpose there is obvious: to build a collective contacts list based on the aggregate of some of the leading social platforms already out there, including Facebook, the world's #2 and Europe's #1.

The API itself is not particularly complex. Developer documentation released this morning shows the SDK adds or amends a class, Contacts, with three methods whose purpose is nearly self-explanatory: Update, View, and Invite. The common thread between these is a delegated authentication provider that serves to exclusively identify each contact. That requires access to the pre-existing Windows Live ID Delegated Authentication SDK for Application Providers, which is Microsoft's system for letting developers embed Windows Live ID authentication in their own programs.

"Delegated Authentication works by sending your users to the Windows Live ID consent page, where they can grant or deny permission for your site to access their data or content on Windows Live services (called resource providers in the Delegated Authentication context)," reads Microsoft's official description. "Resource providers register offers and actions with the Windows Live ID service, and it is these offers and actions to which users grant consent. After a Windows Live ID user has granted your site consent to a given set of offers and actions, your site can then interact with the resource provider on behalf of that user."

Thus it appears likely that Microsoft and/or its partners in this effort may soon try a system enabling independent developers to build applications that contact social network contacts ostensibly through their own respective networks, but that authenticate and establish direct contact with them through Windows Live's authenticators.