Facebook is not sure if it's “100 per cent right” in preventing Google’s Gmail and other third party apps from automatically importing email addresses from the social-networking site.

We're trying to think through these things and be respectful of all the forces that are at play, said Facebook founder Mark Zuckerberg at the Web 2.0 conference in San Francisco on Tuesday.

Google has, several times in the past, raised concerns over Facebook’s reluctance to offer an API that allows users to automatically export email addresses from the social networking service. This grouse of the internet giant came to the forefront earlier this month, when it cut off Facebook's access to Gmail's Contacts API.

Using the Google API, Facebook had offered its users the option of importing their contact names and email addresses from Gmail; while, on the other hand, Gmail was unable to offer its users a similar import from Facebook as the networking site was blocking access to its API.

Even at the conference, Zuckerberg reiterated the claim that his site was preventing exports because users didn't really own the email addresses of their Facebook friends.

Email is a little bit different from social networks. In an email program, if you have an address book, you put all the addresses in there, so that's very much your information. In a social network if you upload a photo album or a blog post, that's yours... But there's information that's clearly not yours, For example, someone else's photo album. But then there information that's somewhere in the middle, maybe a photo they you took but I tagged,” said Zuckerberg.

He also stressed that he's just doing what Facebookers want him to do.

The feedback we get on a regular basis from hundreds and millions of people is more along the lines of 'we want control of all the information we put into the site,” said Zuckerberg.