Drupal is a CMS written in PHP that is getting more and more visibility in the Semantic Web crowd. Several researchers from DERI have been using it as a test bed for their research projects and developed extensions to showcase their ideas. It is for example used to build the Semantic Web Dog Food site that archives the semantic web conferences and publishes them as Linked Open Data. The URL for this year's ISWC is http://data.semanticweb.org/conference/iswc/2009
This led me to read more about Drupal than I had had the incentive before. I have not had time to give it a try, but I skimmed the documentation and will try to compare it with CubicWeb from a software architecture point of view.
Drupal defines a Node as an information item. The CCK (aka Content Construction Kit) can be used to define new types of Nodes thru a web interface. Nodes and the bits and pieces used to display them as HTML are not packed together in components. The Features extension is planning on getting this bits packaged.
If you are a Drupal user/developer and think I am not being fair to Drupal, please comment below.
On the other hand, CubicWeb has implemented very early the concept of reusable component. What is called a Node in Drupal is an Entity in CubicWeb. By design, CubicWeb does not have a web interface to define entities. The data model is part of the code. To efficiently maintain applications in production, changes to the data model must be tracked with changes to the code. Data model changes imply migration procedures. In CubicWeb, all of this is versionned and made part of the components. Where Drupal needs to grow extensions like CCK and Features, CubicWeb has more advanced possibilities by design, for example the ability to develop featurefull applications by assembling components.
This was a very short comparison. I'm looking forward to getting a chance of discussing it with knowledgeable Drupal hackers.