Convention versus standard

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

The dictionary defines the word "convention" as this:


    Convention: A rule, method, or practice 
                established by usage; custom 


For example, by convention street signs in the U.S. are placed at
street corners, we expect to find them by looking up, not down, and we
expect them to be horizontal, not vertical.  The benefits of this
convention are:

   - we can locate street signs quickly, 
     with a minimum of effort
   - their appearance makes it easy to 
     distinguish them from everything else

Another example: by convention books have table of contents that occur
somewhere in the first few pages, page numbers are somewhere in the
margins, and they will look like a table of contents and page numbers.

The dictionary defines the word "standard" as this:


    Standard: Something considered by an authority 
              or by general consent as a basis of 
              comparison


For example, the XML specification is a standard.  It requires, for
instance, every XML document to have a root element.

I observe a couple differences between conventions and standards:

    1. Using a convention is advisable, but not required.  
       The things listed in a standard are required.

    2. Conventions are the product of a bottom-up, grassroots 
       evolution.  Standards are generated top-down by an 
       authority.  


QUESTIONS

What conventions have formed in the XML community?  Are there any
conventions that have become universally accepted?  Are there
conventions that have been adopted only within a community?

Conventions typically evolve over time.  Do you anticipate an evolution
of conventions within the XML community?

/Roger