Ron Hulen concludes that Agile must be going mainstream because so many people he spoke to at the Agile 2007 conference have worked on an Agile project.

I was similarly surprised to discover that most attendees at a recent Steve Vai concert own at least one Steve Vai CD.

Seriously, though. If you find yourself in a group with high incidence of some property (e.g., everybody owns an iPhone), you could be forgiven for thinking it applies universally. Sometimes, though, it's just because you're inside a clique.

It's still very interesting, though. Evolutionary psychologists suggest we evolved to deal with "village-sized" populations and the statistical effects that occur on that scale. It explains why we read supernatural significance into the extraordinary coincidences that can often occur in a population of 6 billion people. It also might explain why we interpret uniformity in our immediate social networks as universality.