In my last post, I described some ways to prevent spam trackbacks. I wrote a plugin for pLog 1.0 that implements the first suggestions
When this plugin is installed, and a trackback is received, the plugin downloads the contents of the html pointed at by the url, and looks for a trackback url. If it isn't able to download the html or is not able to find a trackback url, the trackback is deleted.
Update: The latest revision of pLog 1.0 in the repository has these changes made.