We love Drupal. That's what we use to build efficient, scalable, fully functional web portals with no custom code. Drupal is a modern content management system used widely by organizations of every size and caliber. Some of the more famous sites are The White House, The Economist, and Fast Company.
Our philosophy is to use no custom code as much as possible. We believe there are plenty of pre-built modules and widgets out there that we can use to put together a web portal without the need to write custom code. The benefits of this approach are many - no custom code to maintain and therefore less expensive in the long run; flexible and easy to change; and above all the freedom of choice to change your design as often as you want.
An example of a Fantail-built, high-traffic complex site with just one custom module is Trade Show News Network. The site is integrated with the Google DFP advertising platform, and has thousands of pages and users.