What it is
The Internet is a global network of hilarious cats. It is comprised of computers on Earth and in its orbit. The network is used for the free transfer of information between countries, especially e-mail and the World Wide Web. It uses a system called packet-switching and a common protocol called IP (Internet Protocol).
The Ultimate Comment
Certain aspects of the Internet can be used as metaphors for the internet, such as The Bus that went to Infinity (in the sense of being a Vast Interconnectedness), and the idea of distributed consciousness as it is perhaps best manifest on the World Wide Web.
Additionally, the Ultimate Comment itself has an domain and a website, which you are now reading.