In line with our Yammer and Office 365 roadmap, we’re releasing a new feature that more deeply integrates Yammer and Office 365: user mapping. When you opt into Yammer as your default social experience in Office 365, Office 365 users are mapped to their existing Yammer accounts. This means that when you click Yammer from your Office 365 global navigation bar, you do not need to authenticate again. Office 365 users without existing Yammer accounts are taken to a streamlined sign-up and verification process.
Enable user mapping to save your Office 365 users time signing in to Yammer
Administrators can enable user mapping between Office 365 and Yammer in the Office 365 tenant in just a few steps. Sign in to Office 365 using an Office 365 global administrator account. Select Admin, and then select SharePoint. Once you’re in the SharePoint admin center, select Settings. On the Settings page, under Enterprise Social Collaboration, select Use Yammer.com service. Now you’re all set. When you click Yammer from Office 365, you won’t have to log in again. You can start connecting with people using Yammer right away.
You can apply Yammer as your organization’s social network in the SharePoint admin center, on the Settings page, to simplify Yammer login for your Office 365 users.
If you previously made Yammer the primary social experience for your organization, we will automatically backfill your Office 365 tenant with this new behavior and notify you about the update by April 2014. But you can manually enable the behavior today by reapplying Yammer as your primary social experience:
In the SharePoint admin center, select Settings. On the Settings page, under Enterprise Social Collaboration, click the Use SharePoint Newsfeed button to clear it, and then select Use Yammer.com service and click OK to apply the changes. Each of these two updates might take up to 30 minutes to complete. Once the updates have completed, Yammer replaces Newsfeed in the Office 365 navigation. You can still access the SharePoint Newsfeed through Sites.
For additional information, please see the article Make Yammer your default social network in Office 365.
User mapping saves time but it is not a complete single sign-on solution
User mapping does not provide a complete Yammer single sign-on (SSO) solution. With user mapping, you do not need to log in again when you click Yammer in Office 365. However, when you browse to Yammer.com directly or use the Yammer mobile apps, you still need to log in with your Yammer.com credentials.
Compare this to Yammer single sign-on, where you log in using single credentials (typically your company credentials), whether you go through the Office 365 global navigation, use the Yammer mobile apps, or browse directly to Yammer.com. To secure all the entry points to Yammer, we still recommend Yammer directory sync and Yammer single sign-on.
User mapping is just the latest step in integrating Yammer with Office 365, as we continue to move toward a unified identity across Office 365 and Yammer.