I love how fragile the Internet really is. This is demonstrated from time to time and when it is - I'm drawn to it like a police chase on live TV . . . sometimes the root name servers come under attack or someone figures out a neat way to poison DNS caches, or cuts 5 undersea cables . . . and of course there's the myriad of attacks that can be mounted on local network segments (ARP spoofing, poisoning etc.). The whole stack really is pretty much a house of cards that the bad guys don't *really* want to break (because they make money via the Internet just like all the legitimate businesses). Fixing the myriad of problems / overhauling it would probalby be so drastic that it probably won't happen until such a time where something extremely drastic happens and a non-trivial part of the world is offline for an extended period of time.
Well in our most recent demonstration of Internet fragility - it seems that Pakistan took out Youtube for a couple hours recently. The root cause is fairly old and well understood apparently.
I'm a BGP doofus so I'll let this dude explain it: http://www.renesys.com/blog/2008/02/pakistan_hijacks_youtube_1.shtml