How exactly does Poison damage work?

Given the several new IC sets that have 5pc bonuses involving Poison damage, I’m wondering how exactly it works and how one can maximize its potential. So, my questions for those in the know are:

• Does Poison damage scale with Stamina/Weapon Power/Critical or Magicka/Spell Power/Critical, or neither?
• How effective is the Thaumaturge constellation in buffing it (eg does it actually work or is it bugged)?
• Do Bow, Poison Mist (Vampire Line), the Black Widow synergy from Shadow Silk (Undaunted line), and weapon enchants have the only Poison attacks in the game? (note that Werewolf abilities are Disease damage)
• What have been people’s experiences in creating this kind of build? Can one realistically focus on Poison damage for PvP or PvE, or must it be secondary to Magic or another main form of damage?

Given that Thaumaturge buffs Magic, Poison, and Disease damage, it seems logical to spec Magicka to also be effective outside of Poison damage, but doing so would also undermine one’s Stamina pool for Bow abilities and limit set choices since most Poison damage sets focus on Stamina/Weapon buffs.

So, any ideas?