Back in Wrath, I wasn't just a one-man army on 3 servers, I was also about 4 guilds on each server. Whenever someone advertised they were giving a guild away, or selling it very cheaply, I'd snap it up with a low level toon, which was usually a shaman (LW), warrior (BS), or whatever toon had Jewelcrafting on that server.
I like planning ahead, so when I found recipes for the 350-450 range for my crafters, I stockpiled them. LW/BS/JC recipes are usually the most prolific in my opinion, and so a guild bank was a perfect place to store those recipes until I could level the toons up to be able to learn them.
Fast-forward to Cataclysm, and guild perks. I hate waste, and having my quests/looting/kills/crafting count for a guild that I don't care about is just wrong. Besides, it's much nicer to have any of my toons being able to access all of the mats in the main guild bank.
So, I'm trying to consolidate my toons back into my original guilds - Wraith Flight on Demon Soul, Warshrike on Daggerspine, and Psychrometrics on Darrowmere. I've cleaned out or learned recipes in those guild banks, and then sold them for a profit, or at least took a slight loss on what I paid for the tabs. My Ally guild on Daggerspine is 10/10 again, and the 2 Horde guilds on Demon Soul and Darrowmere are almost re-united, with only a couple of toons on each server with a TON of mats and recipes stuffed in their stand-alone banks.
I guess I was inspired to write this because of another solo Wow'er. In it, Skaut was talking about the impression she got that if you're not in a huge guild, you're not going to get anywhere. I respectfully disagree.
After about a month, I'm not level 2 on any of my guilds, but I'm not at 1% either. On Demon Soul, with all my 80+'s, I'm at about 80% to level 2, with an average of 300k experience added the total each day. It could be more, it should be more, but again, my dogged persistence in avoiding waste. I wanted several of my toons to finish out getting the "Crusader" title from the Argent Tournament, the tabard for teleportation, along with the most interesting of the Argent mounts (at least to me), the Dragonhawk.
On Daggerspine, JUST from doing the cooking/fishing dailies, with 10 level 45-60's, I believe I'm around 10% or more.
On Darrowmere, JUST from doing the dailies, with 8 level 30-50's, I believe I'm at 18%. Granted, this belies the title of the post, since I'm not alone in the guild. A very nice person joined the guild after we had a long conversation about how Cataclysm got rid of unnecessary quest items, and they have been graciously allowing me to gain the benefit of their questing XP. Thank you!