I imagine he's made very few sales of BCC on the back of his internet fame (how many people on HN are in the market for Bingo Card Creation software?)
His consulting business on the other hand...
- That alone ensures he will rank top of Google for any Bingo Card Creation based key words.
- Then there's word of mouth from anyone who has ever read one of his articles to anyone who may benefit from using his software.
If I recall correctly- most of his traffic comes in through long tail keyword searches, which he constructs mini-sites for (e.g. Halloween Bingo Card maker). In these cases I expect that keyword matches, and relevant content are a lot more relevant than links from tech sites (which mostly go to his blog, on a separate domain)
I suddenly feel the need to read through his posts again.
So talk all you want in an open forum, just avoid talking to much about the core stuff that gives you a competitive advantage.