Joel Gascoigne:
The idea of the Anti-Todo List is that it is the account of progress for that day. In some ways it’s a “Done” List. This is really powerful, because you can always look back at your Anti-Todo List and see how much you’ve got done (even if the items weren’t on your todo list).
Just like how you get a little rush by crossing something off your todo list, the Anti-Todo List goes even further and suggests that you actually write the items down fresh, and write all the additional tasks you end up accomplishing which weren’t necessarily on your todo list.
I have something like this already. As I mark items off my to-do list, they move to the completed tasks view. However, reviewing this regularly will reveal work patterns and opportunities for improvement.