Is it possible to ensure that URLs of key documents are stable and able to be bookmarked?

Each item of content is assigned a unique, persistent identifier (URL) which remains static throughout its lifetime (i.e. is independent of content/status).  Automatic URLs can also be overwritten with a manually specified URL, at a per-content item level.  This will enable bookmarking and deep-linking of any page within the site.

The front-end architecture includes a ‘clean URL’ option, for presenting URLs without query strings (e.g. /document/1 rather than ?document=1).  User friendly URLs can also be assigned per content item (e.g. good-practice.htm). 

Public sites will be accessible to search engine spiders, ensuring that the content is spidered and indexed by the major search engines.