Most of us apply various forms of metadata when we create or manage content. This metadata helps make our brilliant creations findable. But text-based content has life easy — search engines can also accurately index it. So findability is not so big of a challenge for text assets and parsable documents.
But the content we manage is not all text-based or parsable. We use a lot of opaque assets like video, audio and images. Indexing technologies cannot (yet) effectively crawl these items directly — they must rely on theexplicit application of metadata in order to derive the semantics and context which make the assets findable.