They call themselves a framework, though, not a CMS. And you've compared it to Django, which really is a framework, not a CMS. What part of Django would you say it is most directly comparable to?
The most striking similarity is the template syntax, it uses an Erlang implementation of Django templates. I think it draws some inspiration from Django's "batteries included" philosophy in a couple of ways. It encourages developing with small re-usable modules, like contact forms or blogs, that might be considered similar to the Django apps philosophy. It has an automatically generated admin area for your content/models, but it doesn't have a strong notion of model fields so you might have to do more admin view development (HTML/CSS/JS). It has an opinionated data and deeply integrated data model abstraction, although not being relational it isn't at all similar to Django's ORM.
In Zotonic a single Erlang VM hosts multiple sites (equivalent to Django projects), which can be nice for certain uses. Like most Erlang frameworks it is a little better at handling concurrency and AJAX-y ("realtime") websites than some of the more popular web frameworks, to support this the template language is extended to allow wiring UI elements to controllers without explicitly writing the JavaScript.
