When do you capitalize the word internet?

Do you capitalize the word “Internet?” And when does a proper name become a common noun?

This is an issue of some importance to all online copywriters. It’s bothered us for some time that Internet remains a proper noun – after all, we don’t capitalize Cable or Water or Electricity. But, like the Internet, they are all piped to the house by a utility.

Internet is not associated with the name of a person (like pasteurization or Darwinism) or a trademarked brand name (like Kodak and Kleenex). It’s not even a singular entity – I get mine from Earthlink. Maybe you get yours from Time Warner.

Furthermore, Internet has become the commonest of common words, reflecting its importance in contemporary society. Its rising usage parallels the decline of words including hi-fi, pager and fax.