I recently took a month off from Facebook.

I would say that 95% of communication (excluding face to face) between people I know is conducted over Facebook. In addition to that all events are organised through Facebook, if I didn't have an account I would be missing out.

When I meet someone new I don't exchange phone numbers anymore I exchange Facebook details.

For me at least Facebook is my phone number and email address all rolled into one. If I didn't have it I would be unreachable for a good percentage of people I know.

This might not be typical I'm a younger person with a good percentage of my friends still in college or just leaving to start work.