Traditional library can be understood as a system, that archives the collective information from the mediums produced by our society, by indexing them to shelves. It is assumed that libraries have single ontology by which the books can be categorised to a single shelf. Many machine learning research papers exist for this problem.
Hyper-linked library could be understood in such way, that instead of a medium having one place in the ontology, there could be multiple. Imagine a book as a symbolic link to the physical book.
This aspect changes the machine learning problem slightly as instead of forming a clear hierarchy and simple tree structure, the hyper-linked library is a multi-label classification problem instead of hierarchical multi-class classification problem.
What are the important aspects that one has to consider when moving from traditional library problem towards a hyper-linked library problem? Links to research papers more than welcome!