that is a HIGHLY subjective term.index of important information
if you think about a college course: back when i was in school, an average class met 3 hours/week and was expected to have 2X out-of-class study.
I guess if one were to spend 6 - 8 hours a week for 8 weeks looking through threads purposefully - you'd gain a lot and have a good idea of where to look (an old hint: any thread that zen*******, Vigilante and Eskil participate in would get you pretty far along...).
but, to do a real service to the community - take up Allen's challenge!