Plastered to our guild frontpage during a rough patch where we were closing in on finishing the game's content:
The two blue names were the two bosses pre-TBC that we had not completed at the time. They were shown very clearly as incomplete. Our guild members saw it every day they checked the forums. More importantly, they knew the rest of the server saw it.
It was because of this list that we had the motivation to clear up even the more annoying bosses (read: viscidus). It was because of this that we raided through some genuinely difficult times. And it was because of this that many of us were able to take a serious, prolonged break after Burning Crusade released, knowing we had accomplished what we had set out to do.
Are you using the tools available to you to help push the guild forward, or merely to document milestones?