Automatic population Word Press Database
See Expression Engine Entities, db structure data import and performance for a the related discussion this was part of.
I illustrated how you can create relatively powerful systems with the simple WordPress database modal by populating the database directly using a back end system driven by a well structure data modal.
You do this by creating navigation using the creation maintenance of categories for navigating the relationship, and at every level you can create automatically generated post representing the deferent entities in the database. While the result will be a very de normalized view of the data and can be impossible to maintain through the word press interface it can easily be done by maintaining the structured back end and updating the word press databse.
It is even possible to allow for two way system buy queering posts that have not been auto generated by the back end system.
While I am not advocating this is the perfect way it is a technique that can be used to develop a powerful front end with very little investment.
It can also be used to publish a system to various different front-ends, so you may have a powerful proprietary web site but may want to support varies other interfaces driven by the same data like Web Press blogs white labeling a subset on your system.