In response to your "search" question on the google group, a user can add categories to their page(s) to help others find them. For example Category:History. To add a categoryto a page you would use [[Category:Category name]]. To search for a category you can try "Category:Category name" in the (if you have chosen the Category namespace tickbox in search tab of your preferences ) search or go to the advanced search and check the Category namespace. Hope this helps.