Hidden features of Google Reader

It turns out that Google Reader secretly records our activity. You will not find anything through the interface, however there are several commands to look at the history of some of your actions:

1. All posts you have mailed - www.google.com/reader/view/user/-/state/com.google/tracking-emailed
2. All posts marked as unread (tick "Mark as read" at the bottom of the post) - www.google.com/reader/view/user/-/state/com.google/tracking-kept-unread
3. All posts from the previous paragraph, but which you have not read yet - www.google.com/reader/view/user/-/state/com.google/kept-unread
4. Posts where you clicked a title to view a post on the blog itself - www.google.com/reader/view/user/-/state/com.google/tracking-item-link-used
5. The posts where you clicked links - www.google.com/reader/view/user/-/state/com.google/tracking-body-link-used
6. Read posts, arranged in the order they were read - www.google.com/reader/view/user/-/state/com.google/read
7. Feeds you subscribe to on Google’s recommendation (“Recommendations” section) - www.google.com/reader/view/user/-/state/com.google/recommendations-subscribed
8. Google-recommended feeds that you refused (“No, thanks” in the “Recommendations” section) - www.google.com/reader/view/user/-/state/com.google/recommendations-dismissed

- Peeped in the blog "Google Operating System"