[cschmid]

I disagree; I think a system like Wikipedia shows that a textual and visual format like markdown provides the flexibility to convey pretty much any information. For any formal and semantic storage system, you will probably spend more time adapting it to each specific use case than to actually fill it with content.

[captaincaveman]

yet has no metadata or any semantics, its basically just how you layout text ...

[brimwats]

it can, using plugins. i.e. i use schema.org's things as fileClasses, which are enforced using a metadata schema for attributes which are extensible and excludable. My ontology is based on FRBRoo and I have link visualization for ease of reading.