Mediawiki, the software we're running at https://yadis.org, provides a Discussion sibling page for each main wiki page ('Article page'). You can get to the Discussion page by clicking on the Discussion tab at the top of each wiki page.
These Discussion pages are meant to provide a place where changes to the Article page can be discussed before they are made.
We have used the discussion pages to good effect in preparing the current draft. Have a look at the discussion pages for the clauses of the Yadis Specification.