Mine comes from a guitar tuning, Dropped D Tuning. In order to get a dropped d tuning you have to drop the low e to a low d.
It is a really cool tuning and has alot of balls and chunk to it.
Hence:
DropTheE!!
On a funnier note, on another board I was asked if I liked to take alot of ecstasy and so I liked to drop the e!!
To be honest I never thought of it that way, I like my origin better, it's much more healthy.