One of the most common questions we're asked at Facebook is, "How many friends can you have?" It's an increasingly important question as more people around the world share and connect on Facebook and on the Web overall, but it's also difficult to answer. While the average user on Facebook has 120 confirmed friend connections, that number doesn't account for all the different types of relationships people have in their lives. Thanks to recent research from the Facebook Data Team, we're getting closer to an answer.

Earlier today, I gave a keynote address at the Ad Age Digital Conference in New York in which I introduced a new way to look at the relationships people maintain on Facebook--what we're calling your "active network." Your active network consists of all the people with whom you stay up to date. What makes your active network different from other networks is the way you communicate with the people in it.

Think about the ways you communicate with your friends--whether on or off Facebook. The communication likely falls into one of two traditional types: reciprocal communication or direct communication. Reciprocal communication is a conversation where messages are exchanged back and forth. This can include talking on the telephone, or on Facebook it can mean a Wall-to-Wall exchange or real-time chat. Direct communication occurs when you send a message to someone specific, with or without the expectation of a reply. It can be a one-way Inbox message or Wall post on Facebook, or sending an old fashioned letter or an e-mail.

On Facebook, there's a third and new way you communicate--through the stream. Every time you log into your home page you see a running timeline or stream of the information being shared by your friends and the other things you're connected with on Facebook. The more people share, the more you see in the stream and the more you learn about your connections.

This stream communication, rather than reciprocal and direct communication, forms your active network. Whenever you interact with a story in the stream--whether you "Like" a piece of content, comment on it or simply click on it--the person sharing it becomes part of your active network. When our Data Team measured active networks for users on Facebook, it found that, in any given month, users keep up with between 2 times and 4 times more people than through more traditional communication.