In brief, because it is more robust and open. In a few more words:
- Advanced Meta embedded in the document header or package is not directly accessible by end user
- Easy to Add & Extract. A common complaint about embedded meta is that there is no standard beyond the basics (which are not often employed) and is therefore near-impossible to use at scale. Being based on BibTeX means that a simple copy and paste will add significant added, useful meta
- Self-explaining standard which requires no technical expertise to add
- End-User immediate benefit for adding Visual-Meta. End-users who add Visual-Meta to their own or legacy PDFs have the immediate benefit of Scholarly Copy and not being locked into a Reference Manager, making Visual-Meta more adoptable than trying to establish a new header-meta standard.
- Can survive document format change
- Can survive printing out and scanning and OCR and nothing is lost
- All supported meta can survive document format and operating system updates without becoming unreadable
- Trivially easy for a human reader to verify
- Trivially easy to append to legacy documents and to strip if not desired anymore
- Can handle large amounts of formatting information for reader software to use to reformat and re-present the document as well as provide rich interactions
- In short, it brings the magic of digital text to the (same) surface as the text
Visual-Meta provides robust support for advanced interactions by storing meta at content level: Visual-Meta stores dynamic interactions in a non-interactive medium.
A Visual-Meta PDF document will be able to survive in a hybrid digital-analog environment (Laouris, 2015) and through changes in technological infrastructures for as long as documents can be printed and the PDF document model will be understood. A Visual-Meta document can be printed, then scanned again and with OCR all the benefits of Visual-Meta will be available again, reducing the need for elaborate link re-creating interventions (Morishima, Nakamizo, Iida, Sugimoto, Kitagawa, 2009) (Kolak & Schilit, 2008). Because all the interactable variables, can potentially be recorded in the Visual-Meta, this is a path to full, not partial (Marshall & Golovchinsky, 2004), archivability of interactive text with explicit knowledge presented and included (Carr, Miles-Board, Woukeu, Wills, Hall, 2005). It could also become a powerful tool in analysis and operations of multiple documents, where links could be based on inferable relationships between attributes of a document (Carr, 2007), truly releasing the potential power of digital metadata (Tarrant, Carr, Payne, 2008) and the utility of digital ‘eprint’ repositories (Hitchcock, Carr, et al., 2004).