Social media can be a great thing, but I think it encourages narcissism to some degree. Facebook accounts, tumblr blogs, twitter, etc are all about me me me, this is what I think, blah blah blah. (But hey, I still have all three. =P) It doesn't have to be that way, and I'd argue that social media has a lot of pro's, too. But I find it dismaying to see how often my social media becomes about me, and encourages me to have less of an interest in others...rather than more. That's something I'm always having to fight.
Well, not really relating to narcissism as a mental illness, but yeah.