It all started in summer 2009 at HAR, a hacker camp in Holland.
user:fish did a small radio show at HAR FM from 10:00 till 11:00 every morning about hackerspaces.
When the idea of Signal was born we also had the idea to start the Hackerspace hour again.
And here we are!
The official signal archive: http://signal.hackerspaces.org/archive/