WebMention for WordPress!
WebMention is a simple and modern alternative to the Pingback/Trackback protocol.-- Video by Andy Sylvester
From the spec:
Webmention is a simple way to automatically notify any URL when you link to it on your site. From the receivers perpective, it's a way to request notification when other sites link to it. It’s a modern alternative to Pingback and other forms of Linkback.