Thinking of customer documentation, it may sound sometime efficient to repeat . In other words, it may sound useful to duplicate paragraphs or sentences (changing very little or nothing every time it is copied) or even pictures throughout different manuals.
This certainly makes sense in Customer Documentation, often released as paper documents. Link references are often very tedious to use in hard-copies, as hypertext does not exist. But this does not make sense at all in on-line HTML documentation. Why? Because duplication of meaningful paragraphs or sentences is expensive in terms of maintenance time.
Actually, total suppression of text duplication in internal documents is very easy to achieve. Writers have simply to create new HTML files every time they think some text may be re-used by more than on document. Then, they have to create HTML links to these files, wherever they need to, and without limitation. Care should be taken to not break existing links.
Thus, enforcing this draconian rule throughout a whole internal HTML documentation base is very easy, and could be expressed as: create small files, create small directories, don't break links. We should remember, though, that monitoring of such a feature implementation is not directly possible with the standard tools.
Attachment to email, so easy in MS-Mail, implemented in most mail protocols (like SMTP), is equivalent to content duplication and should not be encouraged. So, what should be the distribution methods for internal documents? They should be, in order of importance:
Exchange means here copy in any usual transmission ways like Email, News postings, paper copies, etc. without restriction.