Apparently, the most likely people to have multiple separate online personas are girls 16-18. It does make you think, especially considering that 65% of LiveJournal users are female, and the most common ages for LiveJournal users are 16, 17, and 18. (Although 21 is the statistically average age, last time we checked...)
Do we really know each other, or are we just taking on whatever personality we (consciously or unconsciously) choose to share?!