I started using something like these a little while back and they're phenomenal. Nothing like being able to answer "what the hell was I thinking 6 months ago?",

I started using something like these a little while back and they're phenomenal. Nothing like being able to answer "what the hell was I thinking 6 months ago?", or a stakeholder's "why are we doing it this way?". Also great for getting a new contributor up to speed. My preferred format is a simple Excel table: ID, Date, Area, Decision, Reason, People Involved.