The First Online Tech Demo!

Gizmodo have a great article on the mother of all technical product demos.
45 Years Ago, Doug Engelbart Gave the Most Important Tech Demo Ever

This demo was the first to use a mouse and keyboard, first to demonstrate 'modern' web technology (such as dynamic linking and hypertext links), and audio visual collaboration across a network link.  In its way it is the first webinar!

If you have a spare 90 minutes I would suggest watching the video - it shows great historic value and technique.