As early as 1990, I recall the guidance on capitalization being, if you are referring to internet as a class of internetwork, (possibly an internal network) the

As early as 1990, I recall the guidance on capitalization being, if you are referring to internet as a class of internetwork, (possibly an internal network) then you use the lower case. If you are referring to Internet as the Internet (that is, the world wide network, globally routable, connecting all sites) you use the capital letter. The difference is between the noun, internet, and one particular internetwork, the Internet. In the last 25 years or so, the concept of an internet has basically disappeared (for the most part, maybe we just call it a LAN/WAN now), while the Internet (soon, according to NYT and AP, internet) is all that people mean when they refer to internet now. Which I guess is how language evolves.