Well, it's automatically updated, all people have to do is get an addon to upload their character data.
Right now you can check the address and order the roster by "Rank", it'll show everybody's guild rank and you can see who is warden, grunt, peon, etc.
Other nifty things from the roster:
1) Uploading the info from the "Amule" (Vaultkeeper) the contents of its bags will show up in a separated "Bank" window in the roster.
2) Writing "Alt" or "alt" in the player note will count it as an alt on the "number of members) right now we have 103 (+2 alts) because only Vegonna and Smiths have "Alt" on the players note.
4) If using PvPLog addon, the PVP data can be uploaded too, and provide some nice statistics like what guild killed us most, what character suffered more in our hands, the best HK/Honor ration on the week, and the same statistics for each character.
5) Team finding, if everybody keeps it updated you can find people that has the same quest than you on their questlogs so you can call them to do it together.
6) etc..
Feel free to inquiries
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