I think it would be fun to have a rolodex of sorts with everyone who comes to each conference - maybe something printed and handed out at registration with atendees names, maybe a picture and their websites - with a place to write notes as you meet each person.
It would be fun
A.) To mark off who you meet and have an action plan of who you still would like to meet.
B.) It would be nice to have a nice print-out instead of a bunch of business cards floating around (at least for me...)
Just a thought!