That's fine, and I know that, but I have never heard of anyone doing that to publish something 'more human' on their blog. Not to say that it's never happened, but when I see some pretty basic typos in a blog post that also sounds like actual human frustration, Occam's Razor says it's fair to assume that a human made those typos.

I've seen non-tech people doing that both by hand and automatically, specifically to make the e-mails and documents look human-authored. I'm convinced this is a very common behavior.