"If you have just attended a conference or an exhibition, taken part in a Speed Networking Event sponsored by a trade organization such as the Chamber of Commerce and have walked away with a large number of contacts and cards you need to no what to do with these new contacts... Business Networking is a professional marketing activity and does not end after you have exchanged handshakes and said goodbye upon first getting to know one another. Work out how to develop those contacts before you make them."
Read his post here
http://www.businessnetworkingnow.com/business-networking-tips/how-soon-should-i-contact-people-i-have-just-met