The growth of the world’s largest social network is slowing in the U.S., which isn’t really much of a surprise, considering that it already has about a third of the population. In
2011 Facebook had about 133 million U.S. users, according to eMarketer, up 14% from 117 million in 2010. This year eMarketer predicts that Facebook will grow to 141 million users, which represents
annual growth of 6%.
Thus in terms of users added, Facebook grew by 16 million U.S. users from 2010-2011, and is on course to add another eight million in 2011-2012. In 2013 eMarketer sees
another six million or so users signing up. These figures suggest that the Facebook user base is asymptotically approaching a stable size that is close to half the U.S. population of roughly 315
million. In the long run, growth will probably simply track the rate of increase in the general population.
Getting half the U.S. population to do anything is an impressive achievement,
considering how diverse the country is. A lot of time and money has been spent (and much more will be spent) studying the Facebook user base, identifying demographic and market segments, and so on.
But the slowing growth rate raises a question I find equally interesting: who are the people who haven’t joined Facebook, and why?
We already have some information to answer
that question, some of which is pretty obvious. Older people are less likely to use the Internet and therefore also less likely to join Facebook. At the other end of the age spectrum, young
children are (supposedly) forbidden from joining, although that rule is pretty much unenforceable. People living below the poverty line, people without high school degrees, and illegal immigrants
are also less likely to have Internet access and less likely to join Facebook.
But all these groups together don’t add up to half the U.S. population. Clearly there are a substantial
number of reasonably well-educated American adults with Internet access who haven’t joined Facebook. I’d be interested to see studies figuring who these people are and why they are
reluctant to join -- information which could also be a boon to advertisers, since this sub-population requires different messaging strategies that aren’t dependent on Facebook.