Do sites such as Facebook encourage narcissistic traits in people?

Narcissism, as defined by Wikipedia, "describes the trait of excessive self-love, based on self-image or ego....

"Sigmund Freud believed that some narcissism is an essential part of all of us from birth and was the first to use the term in the reference to psychology. Andrew Morrison claims that, in adults, a reasonable amount of healthy narcissism allows the individual's perception of his needs to be balanced in relation to others. The terms narcissism, narcissistic, and narcissist are often used as pejoratives, denoting vanity, conceit, egotism or simple selfishness. Applied to a social group, it is sometimes used to denote elitism or an indifference to the plight of others."