PostNuke is software that creates an impressive, dynamic web site and provides the webmaster with a site they can administer with a minimal amount of HTML knowledge through a web browser.
But, PostNuke's functionality can be increased by installing modules, blocks and themes. For example, you can add a forum, a gallery and contact form. You can also change how your entire site looks by changing themes. All of this can be done with just a few clicks in the administration panel saving you hours of time, both in the initial creation of the website and in its day to day maintenance.
PostNuke can do anything from traditional blog websites, to a community members' only website with hundreds of users. PostNuke can scale to thousands of uses but is just as easy to create a small website for friends and family.
Information on hosting companies that support PostNuke can be found at this web hosting review site.