It's an old sales adage: Never stop selling, kid. Never stop selling.
And, he does it because it works. We all know what Fog Creek Software does, don't we? I betcha a number of people here have tried his bug tracking software, too.
Me. I'm currently using FogBugz at a company where I'm consulting. We haven't been using it for long, but it's nice enough. (In the past I've used Jira, Trac, Bugzilla). Overall favorite is Trac.
And, he does it because it works. We all know what Fog Creek Software does, don't we? I betcha a number of people here have tried his bug tracking software, too.