It's a non-academic graphycal chat room.
It uselessly consume bandwidth. Bandwidth can cost a LOT to your school.
In the past, it may have been a vector for a virus infestation of the school network. In that case, it have been branded a security hole and justly blocked.
Wnatever the reason, you just don't ever even try to circumvent the blocking, unless you want to be kicked out of the school, find it impossible to get in another good school and end up working your whole life as cashier in a Mc Donald...
By the way, in a work environment, circumventing that kind of blocks can get you fired.
Electro
January 2012