SteadyState offered a single point of control for many system-protection features that exist in Windows 7, but are no longer managed through a single console.
Windows does not have, by default, a single all-encompassing mechanism for returning the entire system -- user settings, data on disk, etc. -- to a given state. There are plenty of scenarios where this is useful, from rent-by-the-hour PCs to computers in institutional environments like schools or libraries. But for a long time the only way to accomplish something like that was through a not-very-elegant combination of native Windows features and third-party products.
Microsoft introduced SteadyState as a free add-on for Windows XP and Windows Vista, but when Windows 7 came out, admins were dismayed to learn SteadyState didn't work reliably with it, and begged to have SteadyState updated for the new OS. Instead, Microsoft announced that support for SteadyState was being discontinued.