Much will probably be made of William Gibson's visiting Second Life next month. New World Notes calls Mr. Gibson "the man who gave 'cyberspace' its name and its imaginative texture" and says SL probably wouldn't exist without him (though ironically, those even more forgetful of history typically refer to Snowcrash as an inspiration for SL).
I must respectfully disagree. The real creator of cyberspace, though not of the word, is Vernor Vinge, with his novella True Names, which predates Neuromancer by at least three years. The vagaries of SF publication were such that the first two publications of it sank quickly into oblivion--at least it seemed that way to me when I set out to replace copies that I would lend and never get back. The Wikipedia article points to an online transcription of the 1984 edition with illustrations. Go read it, and see if I'm not telling the truth. You'll be glad you did.
Some of the details show the realities of computing in 1981, but the ideas are there: what we call avatars existing in a created world in the Internet, and user-created content is all there is. At one point, the two main characters even assume canine form--gee, did Vinge predict furries? :)
In some ways we haven't made it to the world of True Names yet. I'd love to have displays of the sort that the inhabitants of the Other Plane scorn, and we're stuck with LSL for now rather than programming more directly in Other Plane terms. Go read True Names. Even now, it will change your life.
My being an aging programmer who isn't really a redhead does not influence my opinion in this matter at all.