This is a subject that I'm definitely interested in hearing from others about.
I have a lot of ideas about developing things, whether it be a new website, a new program, or a new network topology. However, I find it the most useful to use my medium-size whiteboard to make a generalized overview of my idea, then writing down specifics in the form of either scribbles or small sketches alongside the overview. I've tried writing things down verbosely and even drawing my ideas on a digital medium, but nothing quite makes me feel as though it's as well-documented as physically writing it out graphically on the whiteboard.
How do all of you best document your ideas? Do you find it best to document them physically or digitally? How specific are you with the ideas—write down everything, or write down the basics and get inspiration as you go?