What is the difference between MBSA and Microsoft Update?

Microsoft Update is a Web site that can scan a single computer and indicate missing/needed updates and install them as a group, as long as the computer is connected to the internet and can reach the Microsoft Update Web site. MBSA allows multiple computers to be scanned for missing/needed updates at one time by remote scan, whether or not the target computers can access the Internet and the Microsoft Update web site. GeekGirl