Alex Mills

When it comes to spam and <a href="https://codex.wordpress.org/Introduction_to_Blogging#Pingbacks" rel="nofollow ugc">pingbacks</a>/<a href="https://codex.wordpress.org/Introduction_to_Blogging#Trackbacks" rel="nofollow ugc">trackbacks</a>, the vast majority by far is via trackbacks rather than pingbacks. Very, very few people use trackbacks for legitimate uses anymore (I’ve gotten less than 5 in the last 8 months) as WordPress, etc. all use pingbacks now as their primary ping method.
I had already installed <a href="http://ocaoimh.ie/cookies-for-comments/" rel="nofollow ugc">Cookies For Comments</a> which successfully stops most spam comments but I still had to deal with the tons of trackback spam. So, I wrote this plugin.
It will disable new trackbacks across your site, both legitimate and spam. However since very few people use trackbacks legitimately, this combined with Cookies For Comments should cut your spam down to next to zero.
Why should I use this plugin over one of those trackback validator plugins?
Most non-Akismet style anti-trackback spam plugins work by connecting to the URL that sent the trackback and looking for a link to your blog. The problem with this is that many spammers actually post links to your blog in their spam posts rendering those types of plugins useless. Even those that check the IP address to make sure it matches are beaten by spam blogs (aka splogs).
In the end it’s up to you what to use for anti-spam, but I personally use Cookies For Comments, this plugin, and then Akismet to catch anything that makes it through.

Disable Trackbacks

Globally disables trackbacks to cut down on spam. Very, very few people legitimately use trackbacks and spammers love them, so it's worthy tradeo …

Matthias Pfefferle

David Shanske

Terence Eden

Generates richer WordPress comments from linkbacks such as <a href="https://wordpress.org/plugins/webmention" rel="ugc">Webmention</a> or classic linkback protocols like Trackback or Pingback.
The limited display for trackbacks and linkbacks is replaced by a clean full sentence, such as “Bob mentioned this article on bob.com.” If Bob’s site uses markup that the plugin can interpret, it may add his profile picture or other parts of his page to display as a full comment. It will optionally show collections of profile pictures, known as Facepiles, instead of the full setences.
Semantic Linkbacks uses <a href="http://microformats.org/wiki/microformats2" rel="nofollow ugc">Microformats 2</a> to get information about the linked post and it is highly extensible to also add support for other forms of markup.
<h3>Privacy and Data Collection</h3>
This plugin collects data from sites that send webmentions for the purpose of displaying richer comments on a site. This data is under the control of the site owner. It is the personal responsibility of that individual or individuals to remove any information at the request of the original content creator. Over time, we will add additional tools to assist in doing so.
<h3>Thanks to</h3>
<ul>
<li>Pelle Wessman (<a href="https://github.com/voxpelli" rel="nofollow ugc">@voxpelli</a>) for his awesome <a href="https://github.com/voxpelli/node-webmention-testpinger" rel="nofollow ugc">WebMention test-pinger</a></li>
<li>Ryan Barrett (<a href="https://github.com/snarfed" rel="nofollow ugc">@snarfed</a>) for his feedback and pull requests</li>
<li>Barnaby Walters (<a href="https://github.com/barnabywalters" rel="nofollow ugc">@barnabywalters</a>) for his awesome <a href="https://github.com/indieweb/php-mf2" rel="nofollow ugc">mf2 parser</a></li>
<li>David Shanske (<a href="https://github.com/dshanske" rel="nofollow ugc">@dshanske</a>) for his feedback and a lot of pull requests</li>
<li>(<a href="https://github.com/acegiak" rel="nofollow ugc">@acegiak</a>) for the initial plugin</li>
</ul>

Semantic-Linkbacks

Richer Comments and Linkbacks for WordPress!

Disable Trackbacks vs Semantic-Linkbacks