I think you might need to be a little clearer here on exactly what it is you're after. In terms of 'handy perlmonks links', we have the Personal Node, the scratchpad, the home node...as for 'assigning levels to knowledge', and 'pieces of knowledge', I think that's all a bit too arbitrary to build into the Engine. Self assessment's fine, but when you try too hard to quantify it, you end up spending more time assessing than learning. If you want a personal expert-system, write one - then it'd be personal. :)