After lurking around the interwebs for examples, it seems that the <comments> tag can point to any web page. This makes sense because HTML rather relaxed anyway.
However, I stumbled upon the more interesting <wfw:commentRss>, which should point to a comment feed. Unfortunately the Well-Formed Web has been dead for around a decade and a specification is no where to be found. A summary on Chris Sells’ web log is still available thanks to the Wayback Machine though.
@cnx got it. e-mail is the storage too, not just the communication medium.
you almost don't need a "website", you just need a blog+comments theme on webmail (assuming sensible hosting, not GMail et al) and similar on mailing lists.
You’re right, @tetrislife, email is also a storage, but a immutable one, which isn’t desirable if one wants to correct typos or update information in a blog. In addition, no current MUA has a layout similar to RSS/Atom readers (categorize entries by source/author). I’m not exactly a fan of HTML email either.
I’m experimenting with a method that should take as little engineering effort as possible for readers to immediately adopt with current technologies. So far it seems to be working:
@tetrislife, I understand it like this: traditionally one would POST the comment to the server, which then insert it to the database to be used the next time the page is rendered. IIUC with Web 3 one’s server would be replaced by a collection of other people’s servers (or mining machines), with the perk of worse efficiency.
My argument is that for a personal blog, there’s no need for a server polling 24/7 for comments; instead the blogger can regenerate the site only when there are new ones. The transport medium can be moved to email, which everyone needs a (shared) server for anyway. The mail boxes can then be exported from local mail box (if one uses mbsync or alike) for private comments and mailing lists for public one. They can then be filtered and formatted properly for the static site and the comment RSS feed.