30 Boxes is a on line calendar that is very simple to use and can be shared. I am not a 100% sure if it will replace my outlook appointment folder but it may replace what my wife and I and some people I work with that use Groove currently to keep a synchronized common schedule.
I only played around with it for about 30 minutes but can see where the net presence of this thing tying into some other social network sites is going to make it very popular and we may indeed be seeing a paradym shift in the way people work their appointment folders etc. [www.30boxes.com]
I still want a web based application like this that will replace Groove but nothing has come close yet.