“If your software fails you,” writes Evgeny Kuznetsov, “it’s not always an indication that something is wrong with the protocol.” Which might be why my webmentions post this replies to begins, “Webmentions are strange, at least in how the WordPress plugin handles them.” Although, upon doing some reading, it’s my understanding that trackback does send a post excerpt, etc., although it’s optional; only pingback and webmention send just the URL.