Can I get statistics on RSS readership?

Question

Is there any way to get numbers on how many people are reading an RSS feed? My understanding of the way feed readers work (e.g. Google Reader) is that they check the feed periodically, cache it, and serve the cached copy to whoever asks for it until it's refreshed - which would imply that there's no way to get reliable numbers on readership.

Follow-up

Lots of suggestions to use FeedBurner, but do they have a way of counting individual readers using a web-based reader like Google Reader? Otherwise it seems like the tracking pixel approach suggested by @ifwdev might be best.

Answer 1

Feedburner provides that info, you can delegate your feed to that service. I don't really know how it works under the covers (as you said, the feed should be checked periodically...) to be reliable.