Azn is another acronym for Asian. It's relation is usually related to young, mostly SouthEast Asian Americans, mainly from the hip hop generation.
In order to find their own identity, Azn youth often use upper and lower case letters in order to communicate in online-slang. While there are uneducated Azn out there acting up, there are those who are educated enough to identify Azn with their own pride and heritage.
Even though many of these youths are born in America and may not even speak their native tongue, using Azn slang to communicate is a way of finding their own identity in an American culture dominated by manstream music such as hip hop, rap, pop, and rock.
I have a nephew embedded in this culture. You would not be able to tell by the way he types on line that he is an A student who excel in sports. Having this Azn attitude is simply a way to push out the steam of realizing that you are born a minority and trying to find your own identity.