According to their report, they haven't received any data requests from Saudi Arabia, Syria or Burma, but they did hand over data to the governments of 57 countries in the first half of 2014 alone [1].

It appears content was also censored at the request of the Saudi government.

[1] https://govtrequests.facebook.com/

How about the United States / China / Russia / Great Britain?

Oh they're on the right side, so it's OK /s

Probably not from any foreign countries but I would bet 110% that they are an open book to the US government.

A problem that is not exclusive to Facebook. In fact, all U.S. companies are open books to U.S. Government employees wielding the right documents.

My point was that a Tor Hidden Service provides anonymity to users in countries whose _links_ to Facebook's servers are policed.

Tor also provides censorship-resistance, through bridges. It is one of the only consistent ways to access the open internet from Iran or China.