Skynet is the name of a military (leased by them, anyway) satellite communications network used (amongst other things, I believe) to remotely control drones around the world. A naming choice that shows its owners, whilst being engaged in a deadly serious business, aren't completely without a sense of humour...
Most folks associate it with the movie series Terminator.
http://en.wikipedia.org/wiki/Skynet_%28Terminator%29 : Skynet is a fictional, self-aware artificial intelligence system which features centrally in the Terminator franchise and serves as the franchise's main antagonist ... with its ultimate goal the extinction of the human race ... Skynet was [originally] a computer system developed for the U.S. military by the defense firm Cyberdyne Systems.
