Why does graphite do?
 

Hello,

I am been hearing of peopel using graphite on there zz/bits. What does it do? I think it is for lubrication but on what? Thanks

The graphite is to lube the gear on the axle and the small "slip on gear" that meshes with the motor's gear. Supposedly it will quite the chattering of the zz's transmission and prevent excessive wear on parts...but zip parts are cheap enough I think I wouldn't bother applying the powder graphite (whose metalic properties aren't healthy for the pcb or motor).
-SlackerZ

Ah so there are no speed beenfits to doing this?

There may be slight speed benefits. The major benefit is just in the form of less friction/longer battery life and reduced noise.

Cool, then if I wanted to use this stuff what exactly would I be looking for in the store?

Powdered graphite, not liquid graphite.