Boasting taunt:
Benefit: While raging, the barbarian can incite a creature to attack her by making an Intimidate check to demoralize. If the check succeeds, the target is also shaken as long as the barbarian is visible and raging or until it makes a melee attack against the barbarian. The barbarian receives a +2 circumstance bonus on this check for every alcoholic drink she has consumed during this rage. This is a language-dependent mind-affecting effect, and it relies on audible components.
Does the special feature of boasting taunt kick in for all intimidate checks or just for the standard action intimidate check? If you could use it with Dazzling Display or Cornugon Smash it would be pretty useful. If it only works burning a standard action it seems like it would rarely be worthwhile to taunt instead of AM SMASH.
Since it doesn't mention using a standard action (unlike some other rage powers), any intimidate check made to demoralize should get the bonuses as long as s/he is raging.
Any ability that does not specify an activation time defaults to a standard action. Boasting taunt seems to imply that it is its own ability, so it would take you a separate action to activate.