Sgt_Kickaxe - 7:43 am on Aug 23, 2012 (gmt 0)

Going through a service like feedburner(owned by Google) may be of help since it regularly updates and monitors their anti-spam capabilities. They have an option to sign up for new posts by email still and you can set up the feed to display specific content.

Also, subscribing to the email feed on some sites also gets you an account to post comments with, without verifying the email address, and the bots on your site may be looking for that in order to spam their links.