You can use

- private tumblr blog

- catch.com

- evernote

- google docs

- emacs org-mode + dropbox

etc.

If you record everything on audio tape or talk only using phone and record it. Or you use gtalk only then legal bodies might take it seriously. But no one is going to take notes written by you seriously.

Is it legal to record phone conversation without other persons consent? I don't k now.