A new thought just popped up in my mind about electronic visiting cards... EVCards...
It would be a small paper like device just about the size of a visiting card. It would work as a sender and receiver, side A sender and Side B receiver. When u need to give your visiting card to someone you just need to stick your and his visiting cards with your A and his B side facing each other.
It must be compact enough to fit in a purse :)...