It would be interesting to have some indication of how many people (or perhaps IP addresses) are following individual RSS feeds. Are statistics available that could show how many "followers" a particular RSS feed has?
There's no way to reliably determine this.. IP's are dynamic, readers like Google Reader could account for numerous readers (or numerous IP addresses).
The only reliable way would be to have a unique user identifier in the feed URLs, and that would only work for registered/logged in users (which would be a bulk of them, most likely)..
Anything like this would require the RSS feed URLs to execute code, rather than be dumb cached files, which would increase the server load, all for something of fairly limited interest.
I think there's more interesting statistics that could be calculated/displayed first, perhaps number of view from Google vs number of views from within StackOverflow?