Elizabeth, I just sent you invitations to 6 of my group boards. Just kidding. But, seriously, you make a good point about correct set up of notifications for group boards. I prefer to turn off notifications for new pins, so that my Pinterest friends and I don't receive an email every time someone adds a new pin. And yes, it is very important to acknowledge and reply to comments. Thanks for the helpful summary!

P.S. If you have a funny picture of a cow, please pin it here: http://pinterest.com/silviakspiva/cows-of-the-world/