pontocinza

When a post is published or updated, Internal Pingback Comments scans its content, finds all internal links, and creates a pingback-style comment on each linked post. It mimics native WordPress pingback behavior but eliminates the need for XML-RPC or outbound network requests.
Works with posts only. No settings page, no configuration.
How it works
The plugin parses post content with DOMDocument — not regex — so it handles real-world HTML correctly: nested tags, encoded entities, relative and protocol-relative URLs. For each internal link found, it inserts a pingback comment on the target post. The comment includes a short excerpt from the source post, with image captions (figcaption) stripped so they do not bleed into the pingback text.
Duplicate detection is precise: the source permalink is stored as private comment meta, and the plugin queries that meta before every insert. Republishing or updating a post never creates duplicate comments. New links added to an existing post will generate their own pingbacks on the next save.
What the pingback looks like to your theme
The comment is stored with <code>comment_type = 'pingback'</code> and auto-approved. Your theme renders it exactly as it would render a native pingback. If your theme does not display pingbacks, the comment will be stored in the database but remain hidden on the front end.
<h3>Disclaimer</h3>
This plugin is provided “as is”, without warranty of any kind. While best efforts have been made to ensure reliability and security, the author is not liable for any damages or losses resulting from its use.

Internal Pingback Comments

Detects internal links in posts and automatically inserts a pingback-style comment on each linked post. No XML-RPC required.

Gabriel Koen

** This plugin now works! ** It broke shortly after I originally uploaded it last year. People are still downloading it, so I decided to make it work. I revamped it and made it totally compatible with the latest version of WordPress.
External Related Posts takes the category, tags or custom taxonomy from your post (or custom post type) and searches Google Blog Search for related posts. External Related Posts then adds a link to that blog to your post and pings them, letting them know you made a relevant post on their subject.
Controls exist for how many blogs to search for, whether to only post links to blogs that accept pingbacks, how many pingbacks to perform, and a randomizer for how often External Related Posts activates (e.g., every post, 50% of your posts, 25% of your posts).
Github: https://github.com/mintindeed/external-related-posts
WordPress.org: https://wordpress.org/extend/plugins/external-related-posts/
Image by <a href="http://www.flickr.com/photos/tobanblack/3773116901/" rel="nofollow ugc">Toban Black</a>; some rights reserved. See link for details.
<h3>Licence</h3>
External Related Posts is released under GPL v2.

External Related Posts

Grabs related links from Google Blog Search, inserts a link to them into your post and gives them a pingback.

Internal Pingback Comments vs External Related Posts