Healing Tide Totem is a level 54 Restoration shaman ability.
Tips and tactics
Healing Tide Totem is a healing raid cooldown which heals all allies within 40 yards of the totem for a small amount every two seconds for ten seconds. It is used mainly in group play and should be used whenever the shaman's party is sustaining heavy, continuous amounts of damage. In five-player parties, it is up to the shaman's discretion when to use it, but in a raid setting it is best to coordinate with the party's other healers on when it (and the other healing cooldowns available) will be used.
The healing provided by Healing Tide Totem is strong, but still much weaker than restoration druids' [Tranquility]. Healing Tide Totem does, however, have a tremendous advantage in that it does not need to be channelled. In raid situations where Tranquility-like throughput is needed for survival, the shaman is still free to place their totem and then cast [Chain Heal], [Healing Wave], [Riptide], etc. to counter the damage that exceeds what the totem is capable of on its own. Also, Healing Tide Totem can efficiently counter effects that do heavy damage but also requirement movement, as it can be placed just before movement is needed and heal the shaman and her allies as they move.
Patches and hotfixes
Patch 7.0.3 (2016-07-19): Healing increased by 60%.
Hotfix (2016-01-07): "Healing Stream Totem or Healing Tide Totem (Restoration) should correctly now continue to heal even when the casting Shaman is under the effects of a Druid's Cyclone."
Patch 6.2.0 (2015-06-23):Totem health reduced to 10, down from 10% of the caster's health. Typo created in tooltip.
Now heals all party or raid members, but amount healed per target has been reduced to compensate.
Mana cost reduced to 5.6% base mana (down from 8%).
Patch 5.4.0 (2013-09-10): No longer a talent and is a baseline ability for all Shamans. Additionally, this totem will now heal 12 raid members (up from 5) when used in a 25-player instance.
Patch 5.3.0 (2013-05-21): Healing Tide Totem has a new graphical effect to differentiate it from [Mana Tide Totem].
Hotfix (2013-05-22): "Healing Tide Totem's heals no longer require line-of-sight."
[Tranquility]. Healing Tide Totem does, however, have a tremendous advantage in that it does not need to be channelled. In raid situations where Tranquility-like throughput is needed for survival, the shaman is still free to place their totem and then cast 
[Chain Heal], 
[Healing Wave], 
[Riptide], etc. to counter the damage that exceeds what the totem is capable of on its own. Also, Healing Tide Totem can efficiently counter effects that do heavy damage but also requirement movement, as it can be placed just before movement is needed and heal the shaman and her allies as they move.
Patch 7.0.3 (2016-07-19): Healing increased by 60%. 
Hotfix (2016-01-07): "Healing Stream Totem or Healing Tide Totem (Restoration) should correctly now continue to heal even when the casting Shaman is under the effects of a Druid's Cyclone." 
Patch 5.4.0 (2013-09-10): No longer a talent and is a baseline ability for all Shamans. Additionally, this totem will now heal 12 raid members (up from 5) when used in a 25-player instance. 
[Mana Tide Totem]. 
