How to join several parties into a command channel, how to write to party leaders and to everyone, and the loot priority a channel gives on raid bosses.
Having created your clan and alliance, some day you will come to need to join more than one party into a group and give instructions either to the leaders of these parties or to all the players in all the groups. For this the game has a thing called the command channel. It helps at sieges, at raid boss farming and at other mass events. In some cases the channel is even a mandatory requirement: if the group is not in a command channel it will not be given the quest item or let in to the boss, as for example when entering to the epic boss Frintezza.
A command channel can be created by members of a clan of level 5 and higher; the clan must have the corresponding skill learned, 
Clan Imperium (it is learned at clan level 5). Without this skill you can also create a command channel: for that you have to buy the scroll 
Strategy Guide from an NPC in Aden, Rune or Schuttgart.
To create a command channel you need at least two parties. The leader of the future channel must be the leader of one of the parties, target any member of the second party and type the command /channelinvite: as soon as you press enter, the command channel is created. All the following parties are accepted into the channel only by its leader. If the party with the channel leader falls apart, the channel ceases to exist too. If the channel leader is disconnected, the leadership of the channel passes at random to another player of the same party, together with the leadership of the party. The leadership of the channel is handed over together with the party leadership by the usual command /changepartyleader.
How to write to the channel
To give commands, that is, to write to the channel, the leader of the command channel uses the prefix ` before the phrase (it is the key with the tilde sign). If you use a single ` before what you write, your message will be read only by the leaders of all the parties in the command channel (the yellow chat colour). If you use a double `` before what you write, your message will be read by all the members of all the parties in the channel: if, say, you write ``move it, everybody will see that message (the pink chat colour).
Loot priority on raid bosses
Now a few goodies connected with the command channel (unfortunately they work on far from every server, and where they do, often wrongly). If your alliance, being in a command channel, dealt the first blow to a raid boss, you get priority on picking up the drop from that boss: for five minutes nobody but your channel can pick the drop up. For this rule to work, a condition on the number of people in the channel has to be met: for ordinary raid bosses there must be more than 18 people in your CC; for the lesser epic bosses such as Queen Ant, Zaken and so on, more than 36; for Antharas, no fewer than 225, and all of them must be in the lair of Antharas.
The tastiness of this is exactly that, if you met the requirement on the number of people in the CC and dealt the boss the first blow, and then another alliance came and farmed the boss, for five minutes after the kill you have priority on picking up the drop. After five minutes, if the drop has not been picked up, the pick-up rules become the usual ones.