I've noticed that social media experts (some of them whose blog posts rise to the front of HN) get their own pages, merely for having won awards or recognition in some social media BS ceremonies. In their case, I think it's the combination of online media savviness and the likelihood that no one will actually read their page that keeps their pages from being deleted.

For how much Wikipedia is assumed to be a tech-geek lair, I'm surprised that being big in computer science/programming/etc doesn't guarantee you a spot. CoffeeScript has its own page but not its creator, for instance.