There seem to be plenty of wikis around, though their content is of variable quality. Wikisummaries has some - http://wikisummaries.org http://wikisummaries.or

There seem to be plenty of wikis around, though their content is of variable quality. Wikisummaries has some - http://wikisummaries.org http://wikisummaries.org Pb book outlines http://bookoutlines.pbworks.com/ http://bookoutlines.pbworks.com/ is another good wiki.. there's a particularly good summary of Dan Ariely's Predictably Irrational there.