In Warsong Gulch, when protecting the flag carrier, take note of the number of enemy priests or shaman around before casting Blessing of Freedom. They can easily dispel it. Also, a level 64 mage can spellsteal it.
Patch 1.6.0(2005-07-12): Will now counter the movement impairing effects of Frostbolt, Cone of Cold, Frost Shock. It will no longer prevent the damage taken by Frost Nova, Hamstring, Wing Clip, Mind Flay, Counterattack, or Blast Wave or the melee and ranged attack speed slowing effects of Cripple.