Microsoft describe IIS as follows:
IIS for Windows® Server is a flexible, secure and manageable Web server for hosting anything on the Web. From media streaming to web applications.
Read more about IIS on Wikipedia.
Memory Validator provides a variety of tools on the IIS Tools menu to help you when working with IIS. See also Working with IIS.
IIS Tools may be disabled or not available if you are not on a Windows Server platform. See the FAQ The IIS Tools menu is disabled, why?
If at all possible:
•Run IIS on the same user account that you run the Memory Validator user interface
or
•Run Memory Validator on the same user account as IIS
•Don't run IIS in high isolation mode