If a site must be run on a native Microsoft platform, DotNetNuke (DNN) is a viable solution. DNN is an ASP.NET, originally an implementation of the popular PHP-NUKE. Like Drupal, it comes out of the box as a rich CMS with similar functionality.
A Content Management System is also known as CMS and is a web based application that allows an easy way for lay people to manage the content of a complex web site. The CMS will provide a method for the managers of the site to create content without the worry of "breaking" the site. The site is created by a programmer with one or more templates so that a consistent look and feel is maintained throughout.