Guilds are formal groupings of players. Guilds will be available to players from near the start of the game, will not be racially-exclusive, and you may join as many guilds as you would like per account. When a character logs in, it will be able to choose which guild it would like to represent. While representing that guild you will appear active on the guild roster and have access to the guild chat. Guild membership will also allow greater out-of-group interactivity, with guild members being easily located on a map, current activities visible on the guild roster, and other ways to keep track of fellow guildmates.
Guilds will be able to work towards guild achievements. As guilds do things together in the world, they earn influence. Guilds are able to spend influence on many things such as guild storage, a calendar, and experience flags. Guilds are also able to claim keeps in WvW. They will be able to fly their guild flag from the keep and use influence to upgrade their keep, fortifying it against attacks.
Out-of-game support for guilds will be also be implemented, with a guild calendar allowing guilds to coordinate events across timezones, guild chat accessible from web browsers, and smartphone apps that will be available for free.