For example the quick reply box.. is a hack..
When you install this forum (vbulletin) its all standard..
But you can customize almost everything the way you like it.
A great way to make your forum more easy to navigate or safe time are adding hacks..like the quick reply box.
Other hacks that could be added, could add to the overall navigation of the site..
Though when they change the layout..(template) they dont use hacks.