I see this phrase get tossed around a bunch by people making fun of hipsters (I haven't actually met any hipsters, so I have no idea how accurate it actually is). In that context, it's a way of feigning superiority, since if something is popular to the masses, then it must be generic.
However, I've found myself saying the phrase a lot simply because most people HAVEN'T heard of the shows, games, movies I like. And it's frustrating. I mention I'm into video games, so people ask me what my favorite game is. When I say it's Persona 4, they have no idea what it is. If I say it's a role-playing game, they have no idea what it is. And to someone who barely plays games, I have zero point of reference, except for comparing it to Final Fantasy, which is waaaaaay oversimplifying it. And hell, I've met people who've never heard of Final Fantasy.
Of course, it goes the other way, too. A coworker asked me if I liked Call of Duty, I say no. One of them asked me if I was too "cool" for Call of Duty. No, I just think it's a crap series. Popularity hasn't stopped me from liking The Avengers or Gangnam Style. But people make assumptions about me because they haven't heard of whatever I like.
Thank god for conventions, which seem to be the only place where I can tell someone I like MLP and no one bats an eye.
