He is talking about people having different threat lists. There is one list, the list generated by the monster with hate he has towards each player.
He says that the threat generated by Provoke and Taunt are dependant on the threatlist of the monster. That's not true.
What Taunt & Provoke do:
1)They generate a static amount of threat. "Taunt II" & "Provoke II" generate bigger amounts.
2)They place a debuff on the monster. While the debuff is active the monster will ignore the threatlist and just attack you.
1) Pulling with either only claims the mob, no threat generation.
2) If someone provokes, any other provoke done during the debuff of the first provoke is ineffective.
3)If someone taunts, any other taunt done during the debuff of the first taunt is ineffective.
1) For threat generation: Taunt & Provoke stack. You can use them right after eachother.
2) In roaming parties, a lot of tanks pull with Taunt & Provoke together. The first one is ineffective, but the second one won't be. Ofcourse it's better to pull with something else, but Taunt & Provoke have a big range and keeps you from having to set another ability.