Google and Facebook separately announced the general availability of their respective data portability programs on Thursday.

Google Friend Connect and Facebook Connect are generally designed to extend social-networking capabilities broadly across the Web.

In the real world, this means making it possible for people to use their previously created Google and Facebook accounts to sign in to other Web sites that accept them. That way, people don’t have to create an account for every Web site that requires one, reducing the number of log-in details they need to remember.

MySpace’s Data Availability Initiative has a similar mission.

These programs also aim to let people port elsewhere content they have entered into Google, Facebook and MySpace, like profile information, photos, notes, list of contacts, comments, status updates and the like.

In its announcement on Thursday, Google said Friend Connect is now available to any Web site publisher and that the social features available can be added by copying and pasting snippets of code, so advanced technical knowledge isn’t necessary.

To access Friend Connect features on a Web site, people can log in using not only their account information from Google but also from Yahoo, AOL and the industry standard OpenID, Google said.

Meanwhile, Facebook urged its users to contact their favorite Web sites and encourage them to implement Facebook Connect, which is already running on places like Citysearch, CNN’s The Forum and CBS’ The Insider.

Still, the grand vision of widespread and seamless data portability is far from complete, as these and other initiatives are fairly recent, and important technology and privacy issues remain unsolved.

For example, days after the initial announcements of their data portability programs in May, Google and Facebook promptly locked horns and have been unable to work out their differences. Facebook blocked Google’s Friend Connect service from accessing Facebook members’ data, saying the Google program violates its terms of services because it redistributes Facebook user information to developers without users’ knowledge.

Google outlined its Google Friend Connect, a service that promises to insert social features into any application and any site.

Sound familiar? It is. MySpace has its friend connect service and Facebook has its version.

Add it up and you have a good old fashioned ground war over this question: Is social networking a feature or a destination site? For Facebook, the answer so far is that latter–of course it would love you to carry it around to other sites. Simply put, everyone wants to be the suitcase that carries your social graph.

According to google:

Websites that are not social networks may still want to be social — and now they can be, easily. With Google Friend Connect, any website owner can add a snippet of code to his or her site and get social features up and running immediately without programming — picking and choosing from built-in functionality like user registration, invitations, members gallery, message posting, and reviews, as well as third-party applications built by the OpenSocial developer community.

Visitors to any site using Google Friend Connect will be able to see, invite, and interact with new friends, or, using secure authorization APIs, with existing friends from social sites on the web, including Facebook, Google Talk, hi5, orkut, Plaxo, and more.

The tug of war is over control and the ground war is just beginning. Who controls these friend repositories? Even in an age of open data there will be aggregation winners. If Google’s OpenSocial gang disperses these networks then Facebook has issues. If Facebook succeeds with its walled garden approach, it stays a winner. Google’s plan: Adopt social standards and APIs from everywhere to let folks connect. The potential for Google: Be the friend aggregator.

Lump in ad revenue and it’s highly likely that Google will get a few sites to go along with Google Friend Connect.

And let’s not forget Yahoo. Even, Yahoo launched its Open Strategy with plans to infuse social networking throughout its sites. The message: Social networking is a feature not a destination.