One of your best posts so far David.
I've always had a lot of respect for Basecamp because of that. Not because you invented Rails or wrote a couple good books but because, somehow, even with a lot of money you managed to keep the company small but also super productive.
I think you should talk more about your context and give real numbers like these more often.
Knowing part of your team and your context well I know that the level of productivity and amount of stuff you guys do (including open-source and writing) is quite impressive. But most of people think Basecamp is a <10 people company with a super simple product and a small user base that happens to make money only because you created Rails.
Unfortunately, a lot of people automatically discard everything you write believing your context is too simple and their stuff is on another level (which I know is not the case).