Capitalizing the word Internet connotes that the technology is important, something few people would dispute. But rote capitalization also treats the complex, dynamic internet like a static objectInternet (capitalization) Many American style guides recommend capitalizing the first letter of Internet, and most major American publications (as well as many Canadian ones) do so. Outside North America, internet is rarely capitalized. capitalize internet
Later people connected networks together. That was called an internet. Eventually most of the networks in the world were connected into one large internet that became known simply as the Internet. In other words, there is a technical distinction between an internet and the Internet. For what it is worth, my iPad wants me to capitalize Internet.