The Refbacks plugin is now updated after nearly two years. The plugin doesn’t need much attention, it always worked it’s based on the Webmentions plugin, and we’d done some work over there that I brought over, including a new retrieval class, improved type support, etc. The way I implemented Refbacks is essentially this. When someone visits a page on my website, and it has a referer string, it forks into the background a process to retrieve that page, verify it does link, and creates a refback comment. Semantic Linkbacks parses microformats and enhances that comment. It excludes links on the same site, as these are handled already by webmention or even pingback. One of the things I’ve used this for in the past is to show mentions of my site on the Indieweb wiki.