How can I find out how many RSS and e-mail subscribers on a website
If a site is syndicating its RSS feed via FeedBurner and have made the stats public, you can easily determine the number of RSS subscribers of their feed using the FeedBurner Chicklet.
Just replace XYZ in the above URL with the feed name and you should see an image representing the RSS subscriber count
see example
This is the sample address of the RSS Feed (this one uses FeedBurner’s MyBrand Feature).
http://feeds.labnol.org/labnol
Grab the feed name (i.e., labnol)
Append http://feedproxy.google.com/~fc/ just before it. The result is :
http://feedproxy.google.com/~fc/labnol