A Forge is a group of artists consisting of at least a 2d artist, a modeller and a texturer, that is supported by NCsoft to make some new content such as new weapons and armour and perhaps even new monsters. This will allow Guild Wars' look to be updated more often than would be possible with just NCsoft alone.
Moreover, a Forge can be "hired" with in-game currency to design unique armor and weapons for exclusive use by a specific guild. The Forge designs and models the equipment and sends it to the guild, and the guild then submits it to NCsoft, who then adds a Crafter to the Guild's Hall capable of making the Guild Specific equipment. To avoid level 5's suddenly wearing high-grade armour, there will be conditions to fullfill before being able to order one.
Think of it this way: the actual Knights Templar would have armour that look like the ones worn by their historical namesakes, and the...say, "Hammers of Light" would wield very shiny Hammers.
UPDATE: well, NCsoft made this statement about custom emblems:
In order to maintain absolute security for every element of the game, we are not able to accept externally designed submissions for inclusion into Guild Wars. However, we have already hosted one official Guild Emblem Contest, and we plan to hold such contests on a regular basis. The emblems that are created in such a competition become available for general use, rather than the use of any single guild. We encourage guilds to consider taking part in such contests if they wish to see their emblem as a possible choice in Guild Wars
basically, this now limits my idea to making content available to EVERYONE. which isn't too bad, really.
as for the external content bit...well, i guess it's gonna take some convincing, or some damn good security measures.
at the very least, 2d artists could still submit designs in a contest.
Petition thread:
http://www.guildwarsguru.com/forum/s...288#post186288
I

). But it could work eventually, but first ANet should work on more immediate issues before putting this in, since all it really does is add more custimization of stuff).