I had meant to share this when it was a little newer, but Blizzard recently posted a Guild Advancement Guide to the new Community Site that explains the basics of guild leveling, achievements, reputation, and some general tips to help your guild do well in all of its endeavors, whether it involves raiding, instances, or just being social and trying to keep a motley crew of friends together and on speaking terms.

Of course the post really focuses on things like the Guild UI, perks and achievements, and the technical side of being in a guild or running a guild, but the tips are great for people who are confused about all of the changes to the guild system in Cataclysm and are looking for some more information about it.