Last week, Facebook announced they reached 500 million members. This milestone is even more amazing considering the growth of Facebook over the last few years. The social networking site reached 100 million members just two years ago. Since February of this year, 100 million more members have joined. Even more amazing is that Facebook averages 115 million friend connections per day.

Social networking author James Fowler explains how the exponential growth of Facebook parallels the grown of other networking technology such as the telephone. "Early on, if you had a telephone, but none of your friends did, it wouldn't have been useful to you...If you have two friends who get a telephone so they can talk to each other, you'll suddenly have two reasons to adopt the technology." Fowler also believes Facebook will reach a billion members, especially with their high growth rate both domestically and internationally.

Some other interesting statistics:

• Facebook members created 400,000 events per day.
• Users have uploaded 40 million photos to Facebook.
• 70% of users live outside the United States.
• Two of the most popular "Favorite Books" when Facebook started, Harry Potter and the Bible, are still among the most popular books listed on members' profiles.

What are some of the unique trends you've seen from social networking sites? Do you see Facebook reaching a billion members, or will the growth rate slow down soon?

For more information, see: http://www.usatoday.com/life/lifestyle/2010-07-21-facebook-hits-500-million-users_N.htm