"If Facebook were a country, it would be the eighth most populated in the world, just ahead of Japan, Russia, and Nigeria." That was what Facebook CEO Mark Zuckerberg was proudly blogging last month. This month, as the number of active Facebook users hit 175M (up from 100M last August), Zuckerberg was blogging about another topic entirely: the question of who owns and controls the information posted by users on Facebook pages.

Here's his posting in full:

"A couple of weeks ago, we updated our terms of use to clarify a few points for our users. A number of people have raised questions about our changes, so I'd like to address those here. I'll also take the opportunity to explain how we think about people's information.

Our philosophy is that people own their information and control who they share it with. When a person shares information on Facebook, they first need to grant Facebook a license to use that information so that we can show it to the other people they've asked us to share it with. Without this license, we couldn't help people share that information.

One of the questions about our new terms of use is whether Facebook can use this information forever. When a person shares something like a message with a friend, two copies of that information are created—one in the person's sent messages box and the other in their friend's inbox. Even if the person deactivates their account, their friend still has a copy of that message. We think this is the right way for Facebook to work, and it is consistent with how other services like email work. One of the reasons we updated our terms was to make this more clear.

In reality, we wouldn't share your information in a way you wouldn't want. The trust you place in us as a safe place to share information is the most important part of what makes Facebook work. Our goal is to build great products and to communicate clearly to help people share more information in this trusted environment.

We still have work to do to communicate more clearly about these issues, and our terms are one example of this. Our philosophy that people own their information and control who they share it with has remained constant. A lot of the language in our terms is overly formal and protective of the rights we need to provide this service to you. Over time we will continue to clarify our positions and make the terms simpler.

Still, the interesting thing about this change in our terms is that it highlights the importance of these issues and their complexity. People want full ownership and control of their information so they can turn off access to it at any time. At the same time, people also want to be able to bring the information others have shared with them—like email addresses, phone numbers, photos and so on—to other services and grant those services access to those people's information. These two positions are at odds with each other. There is no system today that enables me to share my email address with you and then simultaneously lets me control who you share it with and also lets you control what services you share it with.

We're at an interesting point in the development of the open online world where these issues are being worked out. It's difficult terrain to navigate and we're going to make some missteps, but as the leading service for sharing information we take these issues and our responsibility to help resolve them very seriously. This is a big focus for us this year, and I'll post some more thoughts on openness and these other issues soon."