While these aren't necessarily "rules", the following are what follows are the systems, techniques and guidelines that have been developed by the healers on public raids. I am writing this to help clarify some of what we do in healer channel (aside from whipped cream attacks) for new raiders, as well as for returning friends who might have learned another system. Input and clarification are always welcome, as are sensible changes. This is a "living" set of guidelines and they evolve as our encounters, spells, and skills require and allow.
Here is the short version, with a longer "why and how" explanation for each following.
1. All clerics, druids and necros should /join the channel "CLR" at the start of every raid.
2. A CHC (Complete Heal Cycle) is organized by senior healers before each encounter that needs it. CHC is called in its own channel to reduce spam.
3. A FHC (Fast Heal Cycle) is also organized by senior healers in a similar manner. However, we utilize fast heals (primarily Pious Remedy) instead of Complete Heal.
4. Non-cycle heals are called in /say. Do not use CLR to call regular fast heals. Do not use your FHC key as your regular fast heal key.
5. MGB heals are organized in CLR according to mob needs, and called in both raid channel and CLR. Do not use your MGB for buffing unless you ask first, because we may need it for the encounter.
6. Call rezzes in both CLR and raid channel so that the other healers know what's being dealt with, and the raiders and leaders know that rezzes are happening.
7. Call DI (Divine Intervention) in both CLR and raid channel for the same reasons.
8. Buff Smart.
9. Coordinate with group members.
1. All clerics, druids and necros should /join the channel "CLR" at the start of every raid.
Make it part of your habit to join channels in the same order. For example, my routine is always /join raid_channel_name, /join clr. This means your channels are always in the same chat slot, which assists in limiting the amount of hotkey adjustments you have to do. While this seems obvious, I have instructed a couple folks on this basic yet helpful habit. Why do necros join? In the past months, we have utilized CLR as a means of organizing and communicating mana % for dumps. It allows the necros to receive feedback, and allows other healers to adjust or step in if necessary. Also, it keeps other channels clear of information that the raid does not need to hear.
2. CHC
This stands for "Complete Heal Cycle" and is set up as required. Generally, a veteran healer, cleric or druid, will be coordinating with the raid leader so that we can prepare in advance for upcoming fights. The need for a CHC varies, depending both on the healer turnout and gear level. Due to the disparity that comes with being a public raid force, this may mean that while one day we can fight Mob_04 and utilize only fast heals, on another day we might have to set up a CHC.
If we're still organizing the raid or moving to clear a trash area, don't panic if you haven't seen the CHC list in channel yet. Many times, the group setup for trash clearing is different from the tactical arrangement for boss fights. Sometimes, the senior healer isn't sure who is available for what task until the groups are set. In my case, I often wait until we're at the set-up area for a boss, then send a tell to the raid leader asking if groups are set. It saves gray hairs trying desperately to re-organize the list.
Some heathens refer to a CHC as a "wheel". Silly gits.

CHC Format: The person setting up the CHC will call the list of healers in CLR as well as a separate CHC channel. The designated healers will join the channel specifically set up for that CHC. When there is only one cycle needed, I use channel "CHC"; for multiple cycles, such as on the Jelvan event, we use something similarly appropriate (southclr, eastclr, etc.) We use separate CHC channels now to reduce spam for those not in the CHC. Over time, we've found that the spam numbs folks to important info in channel. This is a new method we've used this year and has worked out really well.
Edit:
CHC Order: When the senior healer organizing the CHC calls the list of healers in the CLR channel, that list *is* the order of the CHC. Healers can easily see their place in line and who is next right from that given list. Sometimes the list is drawn up as convenient reading down the raid window, other times there are specific reasons for the order, such as spreading the heal burden among groups or splitting CHC and group heal duties.
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CHC Key: Healers on CHC should have a hotkey created that looks something like this:
/# [ 3 ] CH to (( %t )) ... CAIRDEIL next in 4 sec [ 3 ]
/cast 2
/cast 2
/cast 2
In this case '#' is the number of the CHC channel (mine usually ends up as 7), '3' is that healer's place in line, Cairdeil is the next healer in line, and '2' is the spell gem I use for CH.
There are 3 vital pieces of info in the hotkey:
One, the next healer's name is in caps so that it is easily seen; two, your place in line, so we can see if there's a gap and where to jump in if someone dies; and three, the pause between your message and when the next person should cast. We don't put pauses into the key itself because it can have nasty repercussions with any lag.
I also strongly encourage multiple /cast lines. By doing so, if you fizzle the game will automatically be casting again; if you don't fizzle, it will ignore the extra /cast commands. With the extra lines, you don't have to mash your key multiple times. I have trimmed all the cutesy stuff out of all of my raid keys so they take as little space on others' windows as possible. If we are all using this method, and take pains to make our hotkeys clear and simple, we work more efficiently and smoothly on encounters.
3. FHC
This stands for "Fast Heal Cycle" and is basically exactly the same as a CHC, except (amazing!) we use our fast heal instead of CH. Setup is similar, with the designated healers joining a specific channel (I use 'FHC') and calling their heals there. Usually there is no pause at all; you see your name, and punch your button. I like at least 4 healers on a FHC, which allows spell gems to refresh shortly before it is our turn again.
Don't use the same key for regular fast heals and FHC. All that accomplishes is spamming other FHC members and numbing them to watching that channel for important info. Besides, it's really, really annoying. The excuse of "too much trouble to make another key" is pretty thin, particularly with the multiple hotkey banks we have available now. I have 2 hotkeys, and it's MUCH faster for me to replace my active fast heal key with the FHC key in from my 'standby' set than to remake a key each time.
FHC Key: Healers on FHC should have a key built something like this.
/# [ 4 ] Fast Heal to (( %t )) … CAIRDEIL next! [ 4 ]
/cast 3
/cast 3
/cast 3
Note this is very similar to the CHC key, with the only differences being the spell gem (corresponding to your fast heal) and the absence of a timer.
One last time, do not use your FHC key as your regular fast heal key.
4. Non-cycle heals are called in /say.
Non-cycle heals include healing your group, assigned offtank heals that don't require a specific cycle, and assist heals on mobs that may blur or change targets.
Do not use CLR to call regular fast heals. This is the "default heal" mode for raids. Unless there is a specific cycle set up for bosses, this is what we use. Please DO call your heal, and whom you are targeting. Do not use CLR for this, as it would spam us to death. The result is that /say gets the spam, but it is necessary so we can see where heal gaps exist. Additionally, you can filter out /say easily on trash clears and not miss anything of importance. That isn't the case with CLR or other raid channels.
Clerics, don't use your Light spells for general fast healing. Since the rest of us are using a faster casting Pious Remedy, by the time Light resolves the healing is almost always done, and the mana to cast Light is wasted.
We also utilize non-cycle heals on mobs with extreme DPS--such as Tacvi--where there is no way a mere CHC or small FHC could handle the damage spikes. Here, we have to use regular ol' fast heals and watch /say carefully for gaps and clumps of heals. See a gap? Cast then. See 4 people cast simultaneously with yourself? Duck out if you were last to /say it.
Sometimes, people are unfamiliar with the term "assist heals". These are simply regular fast heals where you got your heal target from assisting the mob. Every healer should have one basic assist key that consists of nothing but "/assist". For this type of healing, Cycle NPC with the leadership AA Health of Target's Target (HOTT) is your best friend. If you haven't already, assign a key to "cycle NPC" key. Under Options --> Keys --> Target find "Cycle through closest NPCs" and assign it to something convenient. Mine is assigned to "E", because like right-thinking people everywhere I use WASD for movement. Then, when we're clearing trash mash that key and watch the HOTT. If the mob's target needs healing, /assist the mob with your assist key and heal them pronto. Voila, assist healing.
5. MGB heals
These are organized in CLR as needed, and announced in raid channel and CLR. Don't use your MGB for buffing unless you ask first, as we may need it.
Format: A senior healer calls for MGB sound off. If your MGB is available, say "Up" in CLR. If your MGB is not available, just say "Down". We don't need detailed info unless asked for timers

MGB Heal Key: If you are on the MGB list, make a key like so:
/4 MGB Heal inc! CAIRDEIL is next! [ 5 ]
/5 MGB Heal inc! CAIRDEIL is next! [ 5 ]
/tell cairdeil MGB Heal fired -- You're next.
In this example '4' is the raid chat channel and '5' is CLR.
When it's time to run the MGB Heals, it is important to watch your buff bars. As a cleric, if you do not have Celestial Rejuvenation level 3, you run the risk of your spell not taking hold, as it will not overwrite the higher levels. Therefore, make sure the previous person's MGB heal has faded before hitting your key. If you do have Celestial Rejuvenation level 3, waiting for fade allows us to maximize the amount of time our raiders are being healed. While an extra tick may not seem like a lot, over the course of a fight it adds up--six healers not wasting a tick is like having an extra MGB'er.
Personally, I do not use /alt activate codes to activate MGB and CR within my key, because I like to see when everything is refreshed or not. That's a personal preference thing though; we don't require folks to do it one way or the other.
Edit:
After thinking about it, I have started using Kelladorn's MGB key format with /alt activate codes. Now that we can have multiple banks of hotkeys visible (I routinely have 3 up), I can both monitor whether my MGB is refreshed, and have a comprehensive key that takes care of all the button pushing.
MGB Heal Key with /alt activate codes:
/alt act 35
/4 MGB Heal inc! # NAME # is next [ 6 ]
/5 MGB Heal inc! # NAME # is next [ 6 ]
/alt act 394
/tell Name MGB Heal Fired -- You're next.
Where '4' is the raid channel, '5' is CLR and 'Name' is the next healer in line. 35 is the alt activation code for MGB and 394 is Celestial Rejuvination.
/Edit
6. Rezzes.
Call your rezzes in both CLR and the raid channel so that the other healers know what's being dealt with, and the raiders and leaders know that rezzes are happening. While it's sometimes unavoidable, it also helps us not rez people multiple times while other people are still waiting. In some cases, we need to recover quickly, and can't afford to waste time duplicating efforts.
7. Divine Intervention
Call DI in CLR and raid channel for the same reasons. Make a DI key for raids. Speed is of the essence here. We want to get DI on the tank ASAP and pull only one healer from heals. If you are new and do not have DI, inform the cleric channel. Oftentimes, multiple tanks will need DI. Coordinate with other healers. DI should be permanently memmed in a spell slot. The longer tanks have to wait for DI, the more time we waste on DIs that are already cast. We do not have time to wait 1.5 minutes for a cleric's spell gem to refresh because they were not prepared.
DI Key: Make a key like so:
/4 DI to [ %T ] !
/5 DI to [ %T ] !
/cast 7
/cast 7
/cast 7
In this example '4' is the raid chat channel, '5' is CLR and '7' is the spell gem for DI.
If you see a call for DI, cast right away. If someone else was faster, duck out and return to healing, and inform CLR that you cancelled. This is very important to prevent everyone assuming someone else cast it. We tell the raid channel so they stop screaming for DI.
8. Buff Smart.
Be smart about how you buff. I can attest that it's frustrating when we're trying to save MGBs, so we have carefully buffed by groups and then noob_cleric_03 comes in and says "MGB Symbol inc!". Communicate! Do not ever MGB Conviction unless it is specifically stated and asked for by the raid leader or a senior healer. We utilize the WoV - Steeloak - Balikor combination, and thus the majority of Convictions will be done singly - mostly for paladins. Likewise, do not use MGB on spells such as Aura of Devotion; it's generally not worth blowing your MGB for.
Edit:
9. Coordinate among group members.
If you are in a group with other healers, please coordinate with them. If you're a cleric with your epic shield, make a hotkey to tell the group when you fire it. In this way multiple clerics know who's got their epic up, who's blown etc. Similarly a group call for RC is appreciated, by other clerics, druids and shamans. Helps keep multiple people from blowing their AAs.
For high end fights where flawless coordination is crucial, like Vish, communication within the group about things like Target DA is very important. When all healers in the party know that Cleric_04 is going to Target DA the MT when he/she screams for it means that the other healers can concentrate on a smooth transition to the ST.
This sounds like a lot of hotkeys, and it is. However there are ways to make it easier. For example, I don't want to crowd my 'primary' hotkey bank with both a hotkey to tell the group and a hotkey for the AA. But, I don't want to just put an /alt activate code into my announcement key, because I like to monitor the ability key directly to see whether it's refreshed. Here's how I cope: I use the extra hotkey banks! I have a hotkey bank (it happens to be #3) as a purely mouseclick and monitor bank. It has no keyboard keys associated with it at all. My RC key in my primary hotkey bank looks like this:
/g RC Inc Now!
/alt act 390
Meanwhile I have the old RC key that you make on the AA window living up in Hotkey Bank 3 so I can keep an eye on it. It has no keyboard keys associated with it, so I can't screw up and miskey it.
/Edit
Edit: Holy Punctuation Mark Translation Fuckups, Batman!