May want to read up on what it is. Providers can use QOS to help control those users that are abusers, or also make it so that all users have the ability of using the service the ISP gives them the same speeds within the limits of the infrastructure.
If ISPs did not control use on their LAN's, you would end up with everyone only getting 1meg down, 56k up on a large ISP in a city. Traffic Shaping is what we are talking about http://en.wikipedia.org/wiki/Traffic_shaping Net Neutrality has nothing to do with this, other than the ISPs have to be fair to all users in their service area, and allow them access to the service. http://en.wikipedia.org/wiki/Net_neutrality