May I highlight that more than 8 million Canadians are on Facebook, that is, one out of four in the nation! If I may humbly disagree and claim that Facebook, for example, reaches way beyond the insiders and digerati. Cheers.
Sad, but true for those of us trying to make a living in social media. It's so easy to fall into the trap that everyone is using (and contributing to) StumbleUpon, Wikipedia, digg, and del.icio.us because you are (and are silently wishing they did).
However, it does seem that everyone is using Facebook, whether you like it or not.
Sure, everyone's logged in to facebook at some point, but the majority of friends i have who are registered never came back, or check it so infrequently that its completely pointless.
And frankly, most of the people who do use it are too busy slapping down zombies to actually communicate, leaving a very small portion of active users.