For Microsoft platform we use DotNetNuke as the content management system. With a large community DNN has many modules ready to implement.
The Datheon platform is a very felxible data platform where you can organize your structured data and query the database. Datheon comes with an API and therefore extendable.
Drupal is a content management platform for buiding professional websites, portals and more. Use Drupal to store your web pages or simply use it as your database.