The last stage of Migration step is Send Out SSO Email. It is a suggestion of sending a Welcome email that contains the application called Single Sign-On.
SSO provides the following features:

  • Initial connection to Exchange mailboxes and related services:
    • Download Outlook 2007/2010 client
    • Upgrade Outlook 2003/2007 to Outlook 2010
    • Download and install OCS 2007 client or Lync Secure IM
    • Configure Outlook profile automatically
    • Change password for a user
  • One-click login to:
    • Outlook client
    • Microsoft SharePoint
    • OCS/Lync
    • My Services

Read the Knowledge Base on Single Sign-On for more information. You may select some of the users, or all, or Skip SSO: