Drupal
With robust content management tools, sophisticated APIs for multichannel publishing, and a track record of continuous innovation—Drupal is ready to stand as the hub of your digital presence.
Drupal is powered by an open source community
Used by the Australian Goverment - full list
List of Drupal sites in government (state, provincial, or national)
Local governments using Drupal
List of intergovernmental organisations using Drupal
Top 10 Universities That Rely on Drupal