A series of tubes. Can become clogged, but that can be remedied by a lotto ball.
"...The internet is not something you just dump something on. It's not a truck. It's a series of tubes. And if you don't understand those tubes can be filled and if they are filled, when you put your message in, it gets in line and its going to be delayed by anyone that puts into that tube enormous amounts of material, enormous amounts of material."
-The Eloquent and Wonderful Senator Ted Stevens (R-Alaska)