If you're a goth, a punk, a big hippie, an international student, or someone who generally isn't used to or wouldn't like a whole slew of white, suburbanite people, you're going to feel at least a little out of place at PSU. As I mentioned before, there are a lot of the same personality types, and you'll find many people fit into certain categories, and it can be a little weird to see how people can be identified so exactly by what they wear (I woke up one day and the weather was warm and virtually of the "sorority-type" girls were wearing the same, floofy short skirt. It makes you question reality sometimes).
Generally people sort of form "cliques" of people who are similar to them, either by country, race, religion, whatever. However, it's important to note that whether you fit in or not, if you don't find a group to fit in with, you'll probably feel pretty lonely. People aren't generally into random social outreach - unless they've been drinking (and even then...). In that respect, even though they may sometimes be descriminated against, special groups - be it Frat boys, LGBT kids, whoever - have an upper hand. However, when it comes to "intermingling," it doesn't really happen all that much. This is part of what makes the culture at PSU so dull.
Most PSU students are from Pennsylvania, since out of state tuition is so high. It seems to me that there are actually more international students than there are out of state students. Also, since I've been living in Los Angeles for the past 8 or so months, I can understand why the one kid I knew from California when I was at PSU felt so out of place - the cutlure is very suburban east coast/central PA culture. Further, there are a significant number of conservative/right wing PSU students - and some of them really feel the need to make their voices heard. In that way there is a kind of balance between conservative students and liberal students (although most students are really pretty passive about politics, etc), however religious there are a number of pretty loud Christian activists roaming campus that keep the campus from feeling completely balanced. One is famous for "preaching" outside one particular building virtually every day, others come and go with Bibles and billboards and handouts. If the thought of these people stepping on your toes makes you uncomfortable, it's probably worth noting that these are the only people who actually suceed at touching a nerve with a regular number of college students - and actually providing the rest of us with something to watch that's not on TV or at a party.