For behind-the-firewall installations, this includes a middle layer ASP.NET web application and a SQL Server database for storage of whiteboard data, enabling uploaded whiteboards to be viewed on a web page. This has the advantage that any notecard that is uploaded with sample code in html, C#, LSL, VB, JavaScript can be displayed on a web page with some simple syntax highlighting. 

For grids that are Internet-facing, this is optional, and only required if you need to have your own private data store for whiteboard data.