Yammer requires some extra set up to enable single sign-on. Follow the steps below to get it set up.
First you need to submit a service request on the following page: http://support.microsoft.com/gp/yammer.
You can also go to your admin portal on Office 365 and raise a support request there. State that you want to Configure Single Sign on for Yammer.
You will receive a response from a first line engineer who will send you a form for you to fill in all the information they require.
Next the engineer escalates it and the new engineer will ask you for your ADFS certificate and your Metadata file, both of which we will supply for you. They will respond with a new Metadata file which we will need to complete the setup.
1) Some mobile or Yammer apps are not SSO aware. You will need to log in with a temporary password the first time, then after that it will work with SSO.
a. To get a temporary password: log onto Yammer.com as the Yammer service account.
b. Under the menu, choose Apps.
c. Under All Apps choose the Yammer tab.
d. Choose the application from the list and it will display a temporary password and email address.
e. Enter those to enable the app for SSO from then on.