It's definitely a great project but it only works if the site have one RSS feed matching the RSS Autodiscovery format (it's OK for most of the blogs).
It would have been much better/usefull if I could subscribe to my RSS reader when looking directly at a RSS feed page (when there's no RSS Autodiscovery) and if the add-on could deal with multiple feeds in RSS Autodiscovery...

This ia a must install add-on! very useful! Thank you developer.

It's often very complex to subscribe to sites that I care about, this extension made it very simple!