If you buff yourself with the maximum number of active buffs (5, all of your active buffs will be applied into a passive buff slot.
I didn't spend that much time looking at it, but when an active aura is in a passive slot this means that it isn't considered in the maximum buff counting (meaning it stacks an unlimited number of times). There's more that you could do with it but theres a lot of experimenting you'd hafta do
As for getting the maximum number of active auras, just get a ton of buffs (scrolls, blessings, w/e). After that, the best way to stack things is just to go get a pally in ur group or get a shammy to lay down a bunch of totems (AoE auras are applied every few seconds, and now that they can stack u get a bunch of the same aura over and over and over).
Go experiment and have some fun. Most servers won't have any clue how to patch it =P
NOTHING if this is made by me i just Copied and pasted it from Citykid199