Here new WordPress comments plugin developed by Donncha (a wordpress dev) – that does “a small plugin that does a small but useful task“. This plugin checks and reports where people leave comments on your blog come from. It then adds a line to the end of your comment notification or moderation email with that small information. This can be useful to see if it’s an evil spammer who is sending an automated post command or someone who actually visited your site and is posted from a particular page.
It is currently a beta release and the first version, but it’s supposed to be working already. If you are interested you can grab it [here].
In case you missed my post about another plugin, this one a bit more about security, by me, do click [here].