The enterprise vs. freelance/consultancy split.
From my point of view, in researching how to set up our WordPress infrastructure, the WordPress community can be neatly divided into two camps: the freelancers and consultants who make their living on WordPress and for whom it’s professionally beneficial to blog about technical concerns, to answer questions on help sites, and to speak at WordCamps – and the folks with jobs in the “enterprise” who are using WordPress as a tool rather than as a career.
The latter set doesn’t say much out in public about their work. They don’t need to promote themselves, and they may be hamstrung by corporate policies that frown upon speaking about one’s work in the public sphere.