A while back, the Reader team added pop-up, tooltip-like windows to the timestamps of posts in the reading pane to show the times that each post was published and added to Reader’s cache. Now there are easily-accessible statistics for each feed, visible after clicking a new “show details” link:
The bar that pops up contains info on the average number of posts per week for that feed and the number of Google subscribers. In these screenshots, I’ve included a sample of what the stats look like for the feed from xkcd.com (a webcomic you may remember, as I wrote a list of my personal favorites a while back).
xkcd’s main feed has about 27,500 subscribers as I write this, and posts approximately 3.3 items per week, which is on par with the stated update days (Monday, Wednesday, Friday).
The write-up on this and a couple other new features actually showed up on the Official Google Reader Blog as I was composing this post. I swear, when I started writing, this was an unannounced new feature. But I will give credit where credit is due, as I wouldn’t have found out about the increased reading area and the new “Most obscure” tab in Trends.