#0 - Oct. 1, 2010, 4:53 p.m.
With the Flexible Raid Lock system, instead of being locked to a specific raid size or raid group, each character will have the opportunity to defeat each raid encounter once a week. You could kill Lord Marrowgar and Lady Deathwhisper with a 10-player raid on Wednesday, join a 25-player raid to kill Festergut and Rotface on Thursday, and then lead a completely new 10-player raid to kill The Lich King on Friday. Every raid has a list of encounters associated with the zone. For example, Icecrown Citadel has twelve encounters. After you defeat Lord Marrowgar, you can open up your character's raid information dialog and see the list of encounters in Icecrown Citadel with Marrowgar marked as defeated. You may no longer fight Lord Marrowgar with any raid size or difficulty until the weekly raid reset for your region occurs.
Another key change is that if you join someone else's raid in progress, you are no longer locked to that raid after merely zoning in. Your raid status will only change when a boss is defeated, at which point it will be updated to reflect the state of the instance in which you are currently participating. So, let's say you have killed the first four bosses of Icecrown Citadel, and you then join a raid that has defeated the first four encounters, as well as Festergut and Rotface. The dialog that displays upon entering Icecrown Citadel will show that the raid has defeated 6 of 12 encounters. If you help them defeat Professor Putricide, then you would be marked as having defeated not only Professor Putricide for the week, but also Festergut and Rotface. If instead after joining the raid you then proceeded to wipe ten times to Professor Putricide, you could leave the raid with only the first four bosses marked as completed.
To help communicate to players which bosses are dead in the raid leader's raid, there is new functionality to link in chat a list of the encounters the raid has defeated. So before you join a raid, you can see what they've already defeated. If a raid leader advertises in chat that she needs another healer for an 8/12 Icecrown Citadel run, you can see precisely which bosses are still available to fight. If you were only looking for that one item from Queen Lana'thel that never drops for you and this raid already defeated her, you will know not to join that raid.