n. A knowledgeable and experienced Internet user.
2005
Neither newbie or knowbie, I count myself among the silver surfers, those geezers in Dickensian nightshirts who preceded the blogging guys in pajamas.
2000
Newbie: Another one of those exclusively Internet type of words. Newbie is slang for someone who is new to the Internet or to some specific aspect of the Internet. A knowbie is, you guessed it, an Internet oldtimer.
1997 (earliest)
Just connected to the Net? Feeling a bit wobbly and shy to show your ignorance? Everyone felt that way once which is why the old hands have set up a Newbie Uni — a New User University. Email, FTP, IRC, Newsgroups, Websurfing . . . from Newbie to Knowbie is what they promise.
This word is a play on newbie, a common term for an neophyte Internet user. (Once used only in the Usenet realm, but now applicable to the Internet as a whole.)