Accepting information from the outside world

'Be generous in what you accept, conservative in what you give'

Diverse flows of information A single node may find itself accepting various kinds of content. Its managers have the power to set parameters on which kinds of information will be accepted, and how much flexibility is built into the system.
Legally binding schemas For those who want ironclad assurances that the content they do receive is the content they expect to receive, the 'schema-as-contract' philosophy, backed up by comprehensive explanations generated by committees, with semantics nailed as closely as possible.
Well-understood relationships In less formal circumstances, where participants know and trust each other, paranoia is typically far less important. In these situations - inside of organizations, or among groups with common goals - it may be easier to ignore the intricate processes needed to generate ironclad assurances.
Thinking as little as necessary Whichever approach is appropriate, no one wants to negotiating every document every time. Some folks want the knowledge used to replace that thought in centralized repositories, distributed repositories, a mixture of public and private repositories, or in local storage.