The replacement ability replaces the destroy effect (such as a card that says to destroy the land) or game rule action (such as being destroyed due to lethal damage). It also removes damage from the land if the land has any. Overall, the ability is very similar to automatic regeneration, except the land does not become tapped when it regenerates, effects that prevent regeneration will not stop Consecrate Land, and if the land is also a creature in combat it is not removed from combat. [D'Angelo 2002/03/16]
Sacrifices cannot be prevented by this card. [Mirage, Page 11]
Does prevent enchantment spells (but not the effects of enchantments) from even targeting the land. [Duelist Magazine #7, Page 99] Indirect effect by enchantments such as Conversion, Living Lands, Kormus Bell, and Mana Flare are not prevented and the land can still be targeted by Gaea's Liege, Cyclopean Tomb, and other non-enchantment effects. [Snark 1994/02/01]
The land can be targeted by land destroying spells and the spell will resolve successfully, but the destroy effect will be prevented from happening. [Duelist Magazine #5, Page 22]
Does not prevent "remove from game" effects that do not destroy the card. This includes Swords to Plowshares (if the land is animated) or Dust to Dust (if the land is an artifact as well). [Time Spiral FAQ 2006/08/30]
Extended tournaments (see Rule 803) banned this card until 2006/10/20 when it became part of Time Spiral.