in reply to
Increasing the Signal/Noise ratio of PM
instead of posting a new message with an errata, just update the original node (possible in most sections of the Monastery). If the update consists in more than fixing a typo you can add it at the end of the post, prefixed by Update:
Personally, I like the Update:s that people put on their posts - it means that I notice any updates they've made if I revisit the node (as I often do when I notice that a node has more replies than it did yesterday).
And why not go "there" when talking about $NORM? Actually I don't think it would matter; $NORM just meant to be a reflection of people's output and input, so if people stopped posting as much as they do, then that would be the norm, so higher XP for everyone would be good (the fact that there's less "noise" would mean that we're all worth more XP in general). I'm confusing myself slightly thinking about this, so I think I'll stop here. Maybe I see why you don't want to go here now.
Update: ok, mirod has just explained to me (in the chatterbox - see, if it'd been posted here, other people would be able to reference it too! :) that if I were to post lots of nodes, then $NORM would go down, so the chance that my next brilliant node would get lots of XP would go up (assuming more nodes means more noise). See the Voting/Experience System page for more info.