Thanks John for your thoughts. The response I got elsewhere in regards to adding code was: Someone would need to lobby WP to allow web mentions? Not many people will manually add the code to their theme I think that this is important and wonder if webmentions will ever be whitelisted (assuming that is what is required.) Interestingly though, this post/webmention did not actually come through. I came upon it via RSS and manually pinged my site. Not sure what is up, but all your comments come via Jetpack it would seem, not via email or any other method. Also, when I go to your blog the posts are not actually included in the main theme. I had to go to 2017 to find them. Might be my site? Might be yours? Might be related to micro.blogs? Really not sure.