Feed analytics#165

It would be nice to have an estimate of how many RSS or Atom feed subscribers we have.

Feeds have always been difficult to extract exact numbers from but this article might offer a good way to approach it within Bear.

This is currently available in the Analytics dashboard if upgraded. It is, however, an estimate. Instead of using the User Agent it logs the unique user/rss requests per 24 hours (since RSS readers poll multiple times a day). If a person changes location (and therefore IP address) then it will log that person as a new reader. I considered just taking that estimate and multiplying it by 0.6, but it feels a bit dishonest even thought it would technically be more accurate.