Mac: Reader Notifier is a free utility that pulls in your Google Reader subscriptions and drops them in OS X Mountain Lion's Notification centre, essentially turning that hidden pane into the most inconspicuous newsreader ever.
Reader Notifier is a bit like previously mentioned News Notifications, but won't cost you anything, and supports Google Reader instead of individual feeds. The app notifies you when new and unread items appear in Google Reader, and displays their titles and excerpts in Notification Center so you can browse them quickly. Click any of them to open the item in your browser.
We liked News Notifications because it was good for keeping one or two important feeds in Notification Center so you could stay on top of important events without being too distracted. If you subscribe to a lot of feeds, Reader Notifier may amount to information overload, but it only notifies you for new items and automatically archives old ones. It's not a bad way to stay up on the events of the day if you don't want a feed reader open in a tab or minimised while you work.