Summary: I was surprised to receive a box with an instruction booklet and a .Mac \"activation key\" which is a 16 digit code that you plug into the www.mac.com website to activate your membership. I was expecting a CD of some sort but this is much simpler and quicker. My wife and I have separate iMac computers and we are constantly updating the iCal calendar and the Address Book. Almost every day we sync our data so that both computers have the same accurate information. The .Mac works like a charm and it runs very quickly. We are also able to share our photos with our family using .Mac. Highly recommended... you can't go wrong with this software.