The purpose of the Yammer Discovery feed is to help you keep up with what's happening in your organization. It's useful for finding out what your leadership team, coworkers, and people in other departments are talking about. So check in with the Discovery tab when you want the pulse of what's happening around you. For keeping track of more immediate concerns, use your Yammer Inbox and the Following tab.
The Discovery tab shows you the most recent conversations related to groups you're connected to, people you're close to and what's trending across your company.
Groups you're connected to includes groups you're a member of, groups where you have viewed messages, and groups that you have posted in.
People you're close to uses data from Office 365 and Yammer, and includes people who have written messages you've liked or replied to, people you have communicated with in a private message, people you have invited to a group, and people who you follow.
Trending messages are recent messages that have many likes or replies.