Google has changed the terms of service for users of its Contacts API to ensure that if data goes out, it can also come back in.

The change is aimed squarely at Facebook, which doesn't allow the automated export of social graph data, specifically contacts or friends.

"Many other sites allow users to import and export their information, including contacts, quickly and easily," said a Google spokesperson in an e-mailed statement. "But sites that do not, such as Facebook, leave users in a data dead end."

Google says that it decided to change its approach because users often are unaware that once they import their contacts into sites like Facebook they don't have an automated export mechanism to get their data out.

Facebook did not respond to a request for comment. The company last month announced limited (manual) information export capabilities, but stopped short of giving users programmatic access to their data or providing a way to remove their data from Facebook's servers.

This new stance may seem like a step backwards for Google, which has gone to great lengths to make most user-owned data portable. But the company insists that it's not limiting user access to data; rather it's preventing automated access through its APIs when services that use its APIs don't offer the same access in return. The idea is to prevent Facebook from implementing a mechanism to automatically copy Google Contacts to Facebook without allowing Google to create a similar mechanism to automatically copy Facebook Friends to Google.

"It's important that when we automate the transfer of contacts to another service, users have some certainty that the new service meets a baseline standard of data portability," Google's spokesperson said. "We hope that reciprocity will be an important step towards creating a world of true data liberation--and that this move will encourage other Web sites to allow users to automate the export of their contacts as well."

Data portability has become a critical weapon against customer lock-in and customer inertia. That's why Google created tools to allow users to move data from Microsoft Exchange and Lotus Notes to Gmail and Google Apps.

But Google is not fully committed to automated export in all circumstances. As Harvard assistant professor Benjamin Edelman pointed out in 2008, Google's AdWords API prohibits automated export of AdWords data. Programmatic access to that data would make it easier for Microsoft, for example, to compete for Google's advertising customers. The contractual language has changed since 2008, but Edelman says the terms say the same thing in a more convoluted form.

"It's hard to see why Google should be allowed to lock up its crown jewels, but Facebook should not allowed to lock up its crown jewels," said Edelman in a phone interview.

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