Improved Shadow BoltFollow

Few specific mechanics questions on Imp SB:
1. Does it increase the damage done by other warlocks, warlock pets, shadow priests, and/or shadow wands?
2. Do casts of the aforementioned classes consume charges of Imp SB?
3. Does drain life count as a periodic or non-periodic damage source? And if yes on #2, does mind flay count as a periodic or non-periodic damage source?

1. yes it increases other locks etc.. damage (including shadow dots)
2. any shadow direct damage (even shadow oil procs off weapon attacks if someone had it on...) takes off a charge
3. drain life is a channeled dot. so it doesn't consume it and mindflay is also a channeled dot