Under Google&39's new terms of service for Google Contacts, it doesn&39't look like Facebook will be allowed to continue letting users find friends through their Gmail accounts.

Google is putting its data liberation philosophy to work in a direct slap at Facebook.

Techcrunch noticed last night that Google made a subtle change to a paragraph in the guidelines that govern how external services can let their users import contacts data from Google. Now those services will have to allow their users to export that data in a manner similar to how Google handles data export, which means Facebook will have to change its policy if it wants to allow users to morph Gmail contacts with Facebook friends.

Facebook has long resisted the notion of allowing people to export contacts data, citing privacy concerns, although it does let people export other data like photos. Google, on the other hand, has long considered data lock-in a cardinal sin of technology companies and has launched the Data Liberation Front to promote the concept of easily exported data.

However, as Mathew Ingram notes at GigaOm, now that Facebook has 500 million users the policy change is a bit late to really force Facebook into having to make any meaningful changes. All it means is that Facebook users won't be able to automatically use their Gmail contacts to populate their Facebook friends list, but they'll still be able to use contacts from Yahoo or Microsoft's services, as well as just find contacts by searching on Facebook.