Creating content in Blackboard Learn is painful and produces ugly content that is not maintainable. No real support is provided for standard authoring functionality (e.g. version control, grammar checking, citation management etc.) No surprise then that most people upload documents (PDF, Word, PowerPoint etc.).
The Content Interface enables
See this blog post for more detail on why and how it works.
See the documentation site for more detail on how and what can be done.
Note: The tool is currently configured so only staff at a specific university can make full use of the tool