Tracking Feed Items

Hi guys,

I was wondering: is there a plugin that allows me to track what are the most popular posts on my feed? I’d like to know which posts are being read from feedreaders. I’ve tested a couple of plugins but none of them seem to work with WP 2.7.

if there’s no such plugin, is there any function / filter that I can use to track which posts are being read from my feed?

Thanks in advance for all your help!