It is unfortunate that it's so tough to track RSS viewers. I'm always tempted to convert the feed to cut-back version just so I can see what posts are actually popular.
An idea I had is to just embed a pixel into the item body. You can self host it too: just analyze the apache logs (or whatever you have) for requests to that pixel.
Feedburner was always the way. Then Google bought it and I’m not sure what happened next
Almost literally nothing other than the domain changing. Don't remind them they have it, they might shut it down :P