In the webmention linkback, the linking site is responsible to inform the linked site about the linking document.
When a new document is added or exising document is updated, the linking site should extracts all the links in the document. For each link it finds in document, the linking site should find the webmention URL and send notification request to the linked site about the linking document.
The linking site should send standard HTTP POST request to webmention URL. The request must contains the following fields:
The response should response as described in spec
There are 3 ways the linked site announce about its interest in webmention notification:
HTTP/1.1 200 OK Link: <document webmention URL>
<link href="<webmention URL>" rel="webmention">
<a href="<webmention URL>" rel="webmention" />
The linking site should download the linked document and scan for webmention URL.