Previously, Facebook’s Download Your Information tool let users export an archive of their status updates, photos, as well as a list of friends’ names, but not their contact information. Now, Facebook allows users to opt into having their email address included in exports by their friends, TechCrunch’s Jason Kincaid reports.

The feature will allow Facebook to deflect criticism that it doesn’t permit data portability by saying that users have the option but choose not to let friends export their email addresses for use in other web services, including Google+.

Facebook launched Download Your Information so users could back up the social content they own, in case they lost their local copy of data such as their photos. It was designed for personal use, with David Recordon, Facebook’s senior open programs manager saying at its launch event “We built this product as something that’s useful for people, not for other developers.” It wasn’t meant to be used to seed a profile and social graph on another web service.

Google and Facebook blocked or put up roadblocks on importing and exporting data between their services in November 2010. Google had accused Facebook of not supporting data portability because users couldn’t export email addresses of friends, but could import addresses from services like Gmail. Facebook responded saying the email addresses of friends are not a user’s own data, and therefore they don’t have the right to export them. Meanwhile, it allowed these same email addresses to be exported through Yahoo! Mail and some smaller third-party email services.

Now Facebook users can authorize their email to be exported when friends use Download Your Information. The option is buried within the folded “Email” settings in Account Settings. Few users regularly visit their account settings, and even fewer would expanded an area that presumably only allows you to change your email address. The placement of the feature here will allow Facebook to say it exists without the risk that most users will actually enable address exporting.

Google’s new social network Google+ bases friend discovery on email addresses, so if users could export the email addresses of all their Facebook friends, they could easily find them on Google+. Facebook clearly doesn’t want this to happen, but doesn’t want to appear to be hoarding user data — a key fear of users that might make them more likely to switch social networks.

Users have little to lose by enabling the option, unless they have friends who would share their email address with unscrupulous developers or spammers. It will make them easier to find around the web, and help friends stay in contact by email if they ever choose to leave Facebook.