People use URI values for many things.

You want to be able to look at the URI and understand what it represents.

Some common metadata in a namespace URI:

• A keyword like 'schema' to denote that it is a schema.

• A path-like structure to "describe" the namespace.

• An owner identifier (e.g. domain name, e-mail address, etc.)

• Version information (e.g. a date or version number)

• Locale information (e.g. 'us', 'en', etc.)