Sci-fi book, recommended in a comment and its children on Reddit ("First book that made my little brain go -pop!- holyfucktheuniverseisfullofpossibilitiesandI'moneofthem").
July 18th: Was reading about 'sousveillance' and found out that this book is about being able to see everything anyone else has ever done - exactly the idea I had that would change people from reverting to selfish barbarian behaviour when they think they can get away with it, and also improve our understanding of each other generally. Wow!
Bought it on the 10th of February 2013 using the voucher Darren and Sandra got me for Christmas 2011.