Textuality - Big Letters

Design Goal: Good Retrieval

HTML Easy to index - hyperlinks make robots possible - not enough structure, but sometimes this is an advantage.
PDF Indexing is unreliable and depends heavily on originating application. No advanced structure search is possible.
SGML The most advanced retrieval environments today are all SGML-based. Has it all: structure, metadata, hyperlinks.
Next
Knowledge is a text-based application.