Wikis present information in a more formal context than forums or blog posts. It's often important to keep track of changes made to a wiki page. The NCDB wiki has a valuable feature called Page Revisions.  This feature keeps track of all changes made to a wiki page and allows you to revert to a previous version of a wiki page if desired. Here's how it works.

When you first create a new wiki page, Page Revisions are not available in the wiki form since this is your first draft.

Once you save the new wiki page AND save an edited version, you'll then see the Revisions select list as shown below.

You'll notice that there are now 2 entries in the Revisions select list. Current State is always the 'live' version of the wiki page, not necessarily the latest version.  The second entry dated 12/18/13 at 9:25pm is the first version of the wiki page.  If, for some reason, I don't want the Current Version of the wiki page to be visible to my group members, I can select the other Revision and that is the wiki page group members will see.