Before doing this function, you first need to have a knowledge of Ajax. Ajax (Asynchronous JavaScript and XML) is used in the Forum application, aiming at updating a whole webpage or a part of the webpage.
This feature defines how the links are generated in the Forum portlet. You can select to use Ajax or not.
By not using Ajax, the Forum will generate plain URLs in the links. The added benefit will be bookmarkability and better SEO as the links will be permalinks.
Using Ajax, the links will be Javascript based and generate Ajax calls. This makes your browsing faster because the whole page is not reloaded.