The usefulness of this totem is specific in PvE but invaluable for those situations. For example, it is excellent versus the corrupted druids in Wailing Caverns, since they can put party members to sleep.
Patch 6.0.2(2014-10-14): No longer usable while under the effects of Fear, Charm, or Sleep, but its duration has been increased to 10 seconds (up from 6 seconds).
Patch 4.0.6(2011-02-08): Tremor Totem can now be used while afflicted by Fear, Charm and Sleep effects, and pulses much more rapidly. Duration reduced to 6 seconds, down from 5 minutes. Cooldown added.
Patch 3.1.0(2009-04-14): Now correctly pulses every 3 seconds, up from 1 second.
Hotfix (2009-02-18):Tremor Totem now properly pulses every 3 sec.
Patch 3.0.8(2009-01-20): Tremor Totem's duration has been increased from 2 minutes to 5 minutes.
Patch 2.4.0(2008-03-25): Tremor Totem now pulses every 3 seconds, down from 4 seconds.
Patch 1.3.0(2005-03-07): Now creates the appropriate looking earth totem; tooltip updated to clarify what effects it counters; radius of effect increased; now pulses more frequently.