I like that Joel decides to say "OK, forget about Subversion or whatever you know about source control in general. I'm going to teach you about the DVCS way from the ground up." It's great that he treats this guide like an introduction to the concept of version control, but I think you really need experience with VCS before you can understand Hg Init.

Is there an easy way to educate older and/or less technical IT professionals about source control? I haven't been able to do it myself, and I wish this was it.