It's hard to say, wrinkles. The prefixis at MC can serve 2 purposes. Numbers are assigned to prefixes these days (that is how come a thread can move above of below the line with no change to title, eg. you wil see non prefixed threads in BS) but outside the splitting of BS, I'm not sure if they serve any purpose outside making life a lot easier for people making text searches (eg, being able to search for "lyr add:" can be very useful). I get the impression you are thinking in terms of the more formal structured way of going about things, which is not overall the way MC works on this aspect.

BTW, on that sort of subject, I've made a new view (lots of other bits to do yet though for the full rewrite from asp into php) for folkinfo using the existing rather more formal apporach. Try this set the date filter at say 1 year to get a few groupings in and try changing the sort to group (hitting go to refresh). On group, it should group by top levels, tech, music and community and within that split music for example up to events, folk songs, etc.