Monotony is a feed reader doing exactly one job: Subscribe to RSS and Atom feeds, Monotony checks for news every minute. News will be displayed on the desktop as notifications, featuring the headline and a summary (if there`s one). To read a news item in your default web browser, just click on the notification.
There is nothing else. No Google Reader sync, no frontend, no possibility to customize it. Monotony runs as a menubar app or, if you choose, invisible in the background. That`s all.
If you want, you can use Monotony together with Growl, the desktop notification system. However, you don`t have to.