Google Reader displays more information about your feed subscriptions — just click on a feed from the navigation sidebar (or type g, then u, followed by the first letters of the title) and you should see the most recent posts from that feed. If you click on "show details", Google Reader has a lot of interesting data: the number of posts per week, the number of subscribers and a histogram of the feed's activity in the past 30 days. The most interesting thing is that you can see how many posts you've read and when do you usually read the posts from a feed.

Source:→ Google System