(Please note that all of the blog posts here are made under the premise of a MMOG built around a 24/7 advancement system that goes forward if the player is online or offline.)
I think it's time that we reimagine what a guild can be in a game, and provide guild leadership with real tools that allow for complete guild customization.
Formation of a guild: first, the capacity to register a guild will be part of the 24/7 character advancement system. An example would be: Tier 1: Leadership > Tier 2: Group Organization (modifiers to group performances) > Tier 3: Guild organization, where this advancement occurs relatively quickly to the point of T3, perhaps a few days. Upon reaching T3, the character can then organize an "open guild".
An "open guild", or a Tier 1 guild, can have 10 signatures of any 10 characters regardless of their skill specs. Open guilds can lead to things like renting local buildings to house the guild, common guild vaults, teleportation stones, discount prices on purchased goods, etc. The founder of the guild can set the guild political scheme to any of various mechanics that actually work in-game: dictatorial, representational, democratic. etc.
However, to advance to a Tier 2 guild, one must have a certain number of characters with certain skill qualifications. Let's say that the leader, representatives or a majority of the guild wants to become a Crafting & Mercantile guild; in order to qualify for such status, there must be at all times at least 5 characters in the guild with Tier 4 or Tier 5 crafting skills.
Becoming a Crafting & Mercantile guild opens up various capabilites and options. First, it greatly reduces prices of publically available crafting supplies and common materials. Second, it increases yield from active, online resource mining. Third, it generates guild revenue by serving the public. These are all subsidiary avenues of crafting guild offline advancement available to the discretionary management of guild leadership.
The Tier 3 Crafting & Mercantile Guild can be something like a Metalworks Guild, or an Alchemal Guild, or a Leatherworks Guild, which specializes in a particular area of crafting, but requires, again, a certain number of characters that specialize in the same area. Note that all of the Tier 2 bonuses to all crafting still apply, but upon embarking upon an area of guild specialization, new bonuses are awarded to any crafter engaged in any form of that craft specialization. In the "Metalworks" Guild example, the T3 bonuses would apply to those who crafted any metal product, from weapons to armor to building materials, to home decor or metal mechanisms.
Specializing is a lengthy process, but yes, the guild can "specialize" in any number of avenues it wishes, given they invest enough time. Specialization gives the guild access to bid on government contracts for products in their line of specialization. Also, if a guild specializes in metalworks and owns a building, they have the capacity to set up their own business instead of using the auction house system.
Now imagine avenues of guild advancement for: Exploration & Adventure - bonuses to running speed, jumping, swimming, climbing, larger "fog" reveals on the map as one moves through new territories, shared fog reveals for all players in the game; detailed map information that appears on mouse-overs, information about items in-game that is hidden from other players without such advancements (which players can gain on their own, but don't have to directly advance if they are a member of a guild that has done the advancing on a guild level), access to corresponding links; Diplomacy & Politics Guild, Mercenary & Protection Guild ... well, you get the idea. These would be tier 2 guild advancement paths equal to the Crafting & Mercantile guild path.
The guild specializations would provide all members of the guild with a set of temporary advancement bonuses in effect only as long as they are actually in the guild, advancement bonuses they could train up themselves in solo 24/7 offline advancement management if they wanted to go that route. Being a member of a crafting guild that specializes in metal fabrication would give a player that has no training in that craft area whatsoever the ability to craft metal items up to a certain level.
Also, it should be noted that leadership can set membership fees in a global, automated system that sends out notes when membership fees are due and then the player can either pay the dues or elect to leave the guild. There would be a great benefit to any player that is a member of a guild, and a great benefit to the guild for having members, especially since member contribution to the status of the guild doesn't necessarily rely on how much time they can spend online.