Google Reader is unarguably one of the best web-based RSS feed managers. With more and more feed subscriptions, it can be irritating to check the reader every few minutes, keeping it constantly opened in a tab and what not. For users of Google Chrome, Google itself has brought the solution in the form of Google Reader Notifier extension.
This extension displays the number of unread feeds in your Google Reader. Clicking the icon can take your directly to the reader itself, or show the new items in a pop-up preview.
In order to work, the extension requires you to have signed into the reader once. After that, you can simply close the tab and the notifier will continue to monitor your feeds for you. Right-clicking will give you access to options where you can decide whether clicking the icon will open the reader (in a new tab) or show the preview, as well as the update interval for updating the notifications. The two small arrows will allow you to move up and down in your list of feeds.
Although there are other Google Reader extensions available as well, Google Reader Notifier is worth checking out since it is an official extension by Google.
Install Google Reader Notifier