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It still irks me to see Internet with an uppercase I when it is not a proper noun. We don’t write about the Phone Company or the Telephone Company, so why is the internet so honored?
Even spell checkers use the uppercase. Or should that be Upper Case? 
For me, it’s because there is only one Internet. “internet” would seem to imply that there are several of them. It is also specifically named.
Umm… it is a proper noun in certain circumstances. There’s ‘the Internet itself’ for instance on one hand versus ‘an internet connection’ on the other.
Because Apple hasn’t purchased it yet.
I’ve never seen, or at least noticed, it to be capitalized. (More likely I didn’t notice, since the letter i is quite thin.)
The Internet is just an instance of the class of internets (i.e. networks of interconnected networks).
There are lots of phone companies. When it comes to The Internet, there can be only one.
Indeed, both AP and Chicago, I’m pretty certain, capitalize it because there is only one. ‘Internet’ in this instance is a proper noun just as, say, National Football League or Major League Baseball is capitalized. There may be the potential for more than one but at the moment there IS only one.
But you don’t capitalize “radio” or “television” (as in “I heard it on the radio” or “I saw it on television.”) Why would you capitalize “I read it on the Internet”?
I’ve stopped capitalizing it because it looks so old fashioned. I also stopped putting the hyphen in “e-mail” when I noticed everyone else spells it “email”.
As others have pointed out – because there is only one Internet. There are many radio stations or newspapers.
never mind. What I wrote made no sense. Sorry.
I’m the opposite: I’m mildly irked when I see internet without the capital I. As others have said, it’s a unique and identifiable entity, more akin to Bob than to accountant.
Daniel
It started off as a proper noun in all caps: INTERNET. See also ARPANET, USENET. They were different actual networks with specific names.
Y’know, I may well be misremembering the all-caps usage. Anyhoo, if you do a search on “internet history”, there should be a multitude of articles that clarify the usage.
“I heard it on the radio.”
The person does not mean a particular station or his personal radio receiver, he means the generic method of information receipt.
I’d agree that “internet” should probably be capitalized, but I think that it will follow the standard of “radio”. It just doesn’t have a face. It’s too abstract to be thought of as a proper noun.
In my book, it’s still Internet, Web site, not website, and e-mail,not email.
And when they do it will be the iNternet.
I don’t think it should be capitalized when it is used in this general sense. It is like “radio” and “television”–the name of a medium.
Is it still “to-day” as well?
You don’t see a significant difference between a linguistic change that happened hundreds of years before your own birth and one that started happening about a decade ago?