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.

"Obviously our launch partners don't cover all the websites you use on a daily basis, so if you want to see this list grow, get in touch with your favorite websites, developers, and services, and tell them you want to connect. With your help, we can all share more information across the web," wrote Facebook founder and CEO Mark Zuckerberg in a blog posting.

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.

"There's an abstract vision for data portability that everyone can agree on, but questions remain," said industry analyst Greg Sterling of Sterling Market Intelligence.