A Data Model that I see / recognize all around the Internet – in all kinds of sites is – a tree. It could have any number of Model Fields beyond – just a name/title. It could have content/description/summary, it could have weights of all kinds, percentages, prices and so on, but in its core – it has a one to many database relation to itself. The data structure is sometimes called virtual file system or hierarchy or it could be directed graph.
The areas where I see it are – web pages, comments (often limited to the second level), tweets, folders, nodes of all kinds of types, technologies, company departments, categories of all kinds – products, articles, software and any thing that has a variation in itself.
I made a video where I demonstrate how my Prototype Studio can generate an app for typing-in and displaying such types of data structures:
And here is the actual app: Tree App