This is a plug-in for Chrome that displays messages from Yammer on the browser page of your browser.  It's convenient to view this on the Web. The icon will change from blue to red when you have new messages on Yammer, notifying you of the number of unread messages you have in your inbox. If you haven't logged into the site, the icon will be grey.

The icon will let you know when there are new messages from people you follow. Yermah is a free Chrome extension for use with Yammer, a social network for businesses. With this extension, you can receive notifications for when a person you follow posts a message or sends you a private message.