I agree with Dave's observation about one-way versus two-way linking of the web, and it reminds me of past experience with trying to make two-way linking for example, linkbacks. I think Wordpress still does this, where if I write a post in Wordpress and another blog in Wordpress links to my post then I get a link back comment intended to show readers of my post what other sites linked to it. I think webmention is the latest iteration of this, and it does appear to add complexity. Link backs were an early attempt at putting a network layer on top of blogs. #