Alliances and Alliance Battles

Characters form a guild; several guilds form an alliance. Up to ten guilds can be in an alliance, so if you join one, you'll have an even larger group of familiar players you can recruit when you're forming a team. When your guild is in alliance, you can visit the Guild Halls of all your allied guilds. Everyone in the alliance can also communicate on an alliance chat channel, accessible through a tab in the chat window. http://www.guildwars.com/gameplay/combat/alliances.php