[MauranKilom]

The most frequent case for me, even on the purely technical sites, is talking about the question author in third person (because writing "question author" or their username [which they might choose to change later!] repeatedly is not really an option).

But even ignoring that, there are several other avenues of communication on SO/SE beyond QA. Comments, different chat rooms, flags, mod messages... And a few of those can be intrinsically personal, so avoiding pronouns may be difficult there too.