It all started 40 years ago today, when a couple of computers were connected by a long gray cable in order to pass some data.  The experiment was funded by the Advanced Projects Research Agency (ARPA) and the project was called the ARPANET.  By the end of the year, four sites were connected.  Today it's hundreds of millions of computers and we call it the Internet.  National Geographic has a story and some video here.  Wikipedia has a nice timeline for the ARPANET here.

Marcus H. Sachs
Director, SANS Internet Storm Center