Popular social network Facebook is saying they have passed 120 million users, but one has to wonder how many of those people are real.

According to CNet, Facebook added 30 million users between the end of July 2008 and the beginning of November 2008.  In addition to their existing 90 million users, this brings their total to 120 million, or approximately 2% of the Earth’s population.  This means that in the past three months, they added more users than they did in the entire first three months of the social network’s existence.

While this is all fascinating, I wonder how many of these users are either a) real people or b) users ever did more than sign up for an account.  I personally know of one person who has two accounts because she forgot her log in information, and after getting into her new account, she decided it wasn’t for her and never logged back in.  I know other people who have created multiple accounts just so they can do better on some of the 280,000 applications on the network, whether those be games, trivia ones or other things

In short, a lot of Facebook’s supposed $15 billion dollar market valuation is based on their number of users, so it is certainly in their interest to show high numbers of members, but people need to think about how many of those numbers are false.  This isn’t to say that Facebook is necessairly intentionally giving out numbers that are partially false, but it is something for investors and advertisers to consider before throwing any money Facebook’s way.  If even half of those users are real, though I imagine it is higher, 60 million active users would still not be anything to sneeze at.