Adding a string "CategorySomething" on a perticular page is in first place nothing but a simple keyword. But there is some magic in place: if you call the page "CategorySomething", this page, if it's existing, will create then a list of all pages containing that keyword. And because it is created dynamically when called, it is definitly up-to-date.

Inventing a new category page is simple: choose the appropriate template - the name is obvious. That's it!

You can add several categories to a particular page. For example, you can add one or more of "CategoryDyalog", "CategoryDyalogDotNet", "CategoryGeneralUtilities".

When you think about a new category, check the list of already defined categories carefully!