His essay on enterprise vs. free approaches to development titled The Cathedral and the Bazaar is also an interesting read and provides some interesting insights behind the unix philosophy: http://catb.org/~esr/writings/homesteading/cathedral-bazaar/
Just realize that it's one guy's take on open source software. He's not more authoritative than anybody else.
The essay became important because it was written at the right time, and because ESR decided to take a role as an advocate to industry. Not really due to its quality.
