You may think that this is of no use to ordinary users but I will disagree. Imagine having limited broadband connectivity, it is smart to be able to prioritize traffic according to the type and also according to IP address (you always want your computer to have the highest priority, right?). In my household, I want my Macbook Pro to have the highest priority for any traffic but I use another desktop for downloading stuff, something that is also of high priority but depending what is being downloaded and by which app. :)
Anyway, this tutorial is more appropriate to network administrators who need to manage their consumption but, as I have mentioned, also appropriate for ordinary users like us.