How would you fit these things into models that exists in the IA/UX community already?

Content Management System and metadata: what role do they play in user experience(1. the implementation of a technology 2. content granularity)
Search : how does this straddles information architecture and interaction design, and if search is directly related to the content and the thesaurus, how do their development play in user experience in general?

Your thoughts are welcome. I'll post more about this later.