Stefan Sagmeister has launched a community site which follows from the title of his recent book:

“The idea for this site originally came out of my own list in my diary, under the very same title: Things I have learned in my life so far. Astonishingly, I have only learned twenty or so things so far. Over the last five years I did manage to publish these maxims all over the world, in spaces normally occupied by advertisements and promotions: as billboards, projections, light-boxes, magazine spreads, annual report covers, fashion brochures, and, recently, as giant inflatable monkeys.

So here I extend this same question to you:
What have you learned in your life so far? What is it that you are fairly sure about? What is it that you believe in by now?” — thingsihavelearnedinmylife.com