You can access the page (internally called a "tab") by its "TabId", for instance: http://www.theiacp.org/tabid/1007/Default.aspx?id=1665
or, just by using query string parameters: http://www.theiacp.org/Default.aspx?tabid=1007&id=1665
DotNetNuke uses a system similar to Joomla (at least I think so) where a page is composed of instances of modules that are placed inside "panes", these panes in turn are defined by the theme a given page uses.
Alas, I guess they have a custom news module where an article can be accessed by supplying an id parameter in its query string.
http://www.theiacp.org/tabid/1007/Default.aspx?id=1660 will point to a different news article. It's technically still the same page however.
http://www.theiacp.org/This/Is/Something/That/Does/Not/Exist...