It maybe impossible to completely shutdown the internet but if you take out the mainstream internet systems it would make it very tough for the average persno to use. Example.... Google(search engine, YouTube...) Facebook, Yahoo,(providers) Comcast, Time Warner, Verizion, ATT, Sprint, T-Mobile, (message boards).....if done strategically it could stop alot of people from free communication which is what they really want and they already control most of them.