Ok, they just updated this one today and what they added I think will help the guild tremendously.
Oh what is it you ask? It's Armory!!! Um NO not the WoW Armory the MOD Armory. It logs your characters as you login and keeps the data for you so you can refer to it when ever you want even across realms. What's more is they just added a feature that if you have armory and everyone in the guild has armory you can actually do a guild search and see if soemone has a pattern/plan/schematic/formula that you are looking to have made. If it finds one or several it will list who knows it under the name of the item. You can also do a guild search by name and view what equipment they are wearing and what their talent build is. And lastly you can view either a certain quest or quest area that people have to see if maybe someone else has the quests you have or has quests in the area you have quests in.
I believe this will also work if you are in a group by using the drop down and change from a guild search to a group search.
What does it save? Well, I mentioned a little above but it saves pretty much everything about your character down to what color underwear you are wearing. Talents, Quests, Skills, Reputation, Spells, PvP Stats, etc....
Pretty much everything you can see by hitting "c" (opening your character sheet including all of the tabs), or hitting "p" (opening your spell list), hitting "l" (opening your quest log), or hitting "B" (opening your bags). It also saves your bank info of everything stored in your bank.
It also comes with ArmoryFU and Armory Titan in case you have Fubar or Titan Bar so you can plug it into those bars as well.
The only thing I can think of them adding to the mix is for it to save the guild bank. I know another mod called Bank Items that saves this information and really that is the only reason I have that one loaded too.
In case you are interested in checking it out it can be found here
http://wowui.worldofwar.net/?p=mod&m=6099 The latest version is 4.1.0. Do not get a version before 4.1.0 or you cannot use the guild search function since that is the new addition.