But unless the blogger uses very specific software (read: excluding static generators), there is no way to know someone has just posted a comment to a post you

But unless the blogger uses very specific software (read: excluding static generators), there is no way to know someone has just posted a comment to a post you wrote two years ago. I'd much rather them send me an email so I can answer in due time rather than let the comment rot, and look like an ass for not responding. Honestly, I understand your argument and I respect it. But if it's a two-way communication, email is better albeit private; if it's between more than two people, then I feel like HN or alike is a better place.