The Single Sign-On service employs two different solutions. The first, Shibboleth, is a higher education community implementation of web single-sign-on using the SAML protocol. The advantage of using Shibboleth is that you can enable access to your site to users from other institutions that are members of the InCommon Federation.
The second, Azure SSO (formerly ADFS), is the solution for Microsoft services such as Office 365 and Azure.