Great way to brush up on studies - UniversityJunction is a new website where college kids can browse through tons of information and materials that have been organized by which class you are actually taking. It's great if you don't feel like you have a handle on whats going on in class, or you want to see how other professors/students are approaching subject matter. It hosts a ton of universities in the US and Canada... and it definitely has a social-network vibe, though the main focus is academics. The only downfall is that some classes are less populated with resources than others, though that should be getting better as it matures.