Last week Digg hosted a great introduction to the Open Stack at their offices in San Francisco. The event included a ton of well-known speakers and advocates of the Open Web like David Recordon, Joseph Smarr, Eran Hammer-Lahav, and Chris Messina. Video coverage should be going up on the Social Web TV shortly, but until then, here's Tom's 5-minute intro to the Open Stack. The "Open Stack" refers to