it would be slick if your site could store notes of this sort. perhaps that's what the articles feature is for?
but what about storing notes mainly intended for personal use and referencing in discussions? other users could see these by viewing a profile or following a link in an article or discussion, but such notes wouldn't necessarily appear under a navbar link.
then, after there was this notion of personal space, there could be a feature like the github activity tracker (on saturday you pushed 2 definitions and a lemma), content could be reviewed (so-and-so agrees that this proof is correct), and these notes could be restructured into discussion topics, articles, and whatnot.