On the usefulness of mailing lists: when I'm stuck on something, transforming the problem so someone else could understand it usually leads me to a solution. So many times I've written up an email asking for help, and then scrapped it because of a new insight while writing.
This is why they say teaching is a great method for cementing your memory. It forces you to master whatever you're explaining so that you can explain to someone else in a way they can understand it.
I often explain things to my computer illiterate wife. Once I break it down enough where she understands it I usually am able to see where I went off the rails.
Similarly, if you truly want to understand a subject, teach it to someone else.
