One surprising trend is that young people generally don't like Twitter, but love Facebook. Why is that? Various pundits have that Twitter apathy among the young is caused by the service's limited number of features, not enough people reading their profiles and lack of safety.

But I think the main reason is that younger people tend to be too narcissistic for Twitter. Wait, too narcissistic for Twitter? How can that be?

Twitter seems to be a narcissist's dream. The conventional view is that Twitter is filled with self-important people broadcasting trivial personal events as if they were of general interest.

But narcissism isn't the same as megalomania (delusions of grandeur) or egoism (total self-interest). The narcissist lacks empathy for others and is overly sensitive to criticism. Twitter is actually a narcissist's nightmare because strangers -- the "general public," potentially -- can read posts and even comment on them in public. To narcissists, non-peer groups are of no consequence and exist only as some irrelevant abstraction. So broadcasting tweets is not interesting, and being criticized in public is terrifying.