Here is one of those things you probably already knew but didn't have any proof for.
Researchers at Western Illinois University studied the Facebook habits of 294 students, aged between 18 and 65, and measured two "socially disruptive" elements of narcissism – grandiose exhibitionism (GE) and entitlement/exploitativeness (EE).
GE includes ''self-absorption, vanity, superiority, and exhibitionistic tendencies" and people who score high on this aspect of narcissism need to be constantly at the centre of attention. They often say shocking things and inappropriately self-disclose because they cannot stand to be ignored or waste a chance of self-promotion.
The EE aspect includes "a sense of deserving respect and a willingness to manipulate and take advantage of others".
The research revealed that the higher someone scored on aspects of GE, the greater the number of friends they had on Facebook, with some amassing more than 800.
Those scoring highly on EE and GG were also more likely to accept friend requests from strangers and seek social support, but less likely to provide it, according to the research.
The article also explains that there have been other studies suggesting increased narcissism among students, though it also points out that the relationship between social media and narcissism is thus far correlational and not causal.
No report yet on what writing a blog about whatever happens to interest you correlates with. I am pretty sure it correlates with being awesome.