Finally, I’ve released yet another but unique anti-spam plugin for WordPress. The formal description:
Publishing of a trackback or a pingback is postponed till someone, usually a trackback author, approves it. Trackbacks which are not approved in 20 hours are automatically deleted. It stops spam from bots and allows trackbacks from the real humans.
A better description is probably a description by an use case:
* Alice has Trackback Confirmation installed.
* Bob has written a blog post with a link to Alice’s blog post.
* Bob checks if a trackback appears in the Alice’s blog.
* No, the trackback hasn’t appeared. But Bob notices the link “approve trackbacks”.
* He follows the links, finds his trackback and approves it.
* Now Alice’s blog links to the Bob’s post.
It’s just a web 2.0 style of trackback moderation. Comments are approved not by the blog’s author, but by the blog’s visitors.