Means, "I know and respect you. Unfortunately, I am also aware that you steal DVDs at parties."
Means, "Hello, we had class together where we spoke a few times. We probably should be friends, but I don't have the time."
Means, "I have no idea who you are, but you seem to know me."
Means, "I am NOT gay, ok? Last night was a JOKE. You better not tell anyone "
Means, "We'd be the kind of guys who call each other "Dawg" if I didn't secretly hate you."
From our book, the CollegeHumor Guide to College.