Come for the art, stay for the amazing ideas.
Kaiser did a fantastic job of thinking about the things that make long campaigns tricky, but rewarding. Keep track of your shenanigans, plan new ones, and end up with something you can look through for continuity (or giggles). Have a new player joining in? That can be so disorienting, but give them a copy of your Chronodex as homework and they'll hit the ground running.
I have a little insight into how much work Kaiser put into this, and though it's being offered free I strongly suggest tossing a few bucks in. This will continue to be supported for the long haul, and frankly it's worth every penny of whatever you give.
[5 of 5 Stars!]