Moka is a Google Reader client for the Mac that runs on the menubar. It has limited functionality if you compare it with other RSS readers, but it has one clear benefit: it doesn't bother you at all and it doesn't take much space. The application will sit on the menubar and refresh your feeds every 10 minutes. You can change this value from the settings menu to "never", 5 minutes or 30 minutes. When you click on its icon, a thin window with your articles will pop up. On my screen, there was room for 8 articles one below the other. Bigger screens might accomodate more articles. Each article has a title, a summary, time and date of publication and the icon for the feed that it belongs to. There are also three buttons in each article. These allow you to preview the article on a second pop-up window, open the article on your default web browser and even share it by mail, Facebook, Twitter and Google+, which can sometimes come in handy.
Navigating your articles is really easy and there are filtering options available to display only articles from specific feeds. Whenever you click on an article, it becomes "read". If you want to, you can also mark all of the articles read from the settings menu.
In short, Moka is a nice Google Reader client, but anyone who has used more complete clients will certainly miss some features that this app doesn't have, like Pocket integration and keyboard shortcuts, to name a few.