Roughly two months ago Blizzard gave us the first tier of the Icecrown Citadel (ICC) raid buff. This buff, if you choose to use it, increased health, healing/absorbing and damage by 5%. Blizzard announced that in future patches and updates the ICC raid buff would go up 10% then 20% and finally be capped at 30%. The reasoning behind this buff was that as time goes on the Lich King would lose power and the Horde and Alliance would get stronger. The buff also goes along with the new World of Warcraft: Wrath of the Lich King (WotLK) policy which is to ensure that everyone gets to experience end game content.
Recently the ICC raid buff has been increased from 5% to 10%. Hopefully this will help some of the guilds that are currently on the Lich King encounter be able to defeat him and move on to hard modes. There is no time table for when the next increase to the buff will be but I assume it will be around when the last raid content of WotLK comes out which is the Ruby Sanctum.