Not entirely sure if it's the same as, but is quite similar to dipping snuff like Copenhagen, Skoal, Timberwolf, etc... used by computer folk all over East Texas.

The advantages are :
Stronger buzz
No smoke
Not having to take a break to support your habit

The disadvantages are :
Constantly hacking and spitting
Cans strewn about with no lids filled with spit
Easy to forget which can you spit in and which can you're drinking out of
Leaves you with foul looking teeth and breath that can melt stainless steel
Breathmints will laugh and run at the sight of the user
Gives user all sorts of strange cancers in their mouths