Show statistics of feeds
Like erstwhile Google Reader, show statistics on feed regarding: last updated, last read, volume of post/day, volume of read/day, etc. Helps user curate content, drop old/non-updating feeds, etc.
This feature was very useful in greader for deciding what feeds to get rid of. You could see how often per day/week a feed posts (great for identifying feeds that are taking up too much of your time), how long it had been since the last post (great for kulling the feeds that haven't updated in years)