g1smd - 2:33 am on Mar 26, 2010 (gmt 0)
example.com/page - is the extensionless URL for a page in the root.
example.com/folder/ - points to the index file in the folder.
example.com/folder/page - is the extensionless URL for a page in that folder.
This is a part of the HTTP specs. Don't break the web by ignoring that - and we see a great many people visiting the WebmasterWorld Apache forum who are having problems with their sites because they chose to ignore the specs.