I agree with evandra that the ending was tidy and sort of betrayed the complexity and the mystery that lead up to it, but it didn't mar my experience too deeply.
Gibson's sense of the dialect of an online-yet-not-geeked-out culture is impeccable, and he suavely connects our lingo with the mainstream. There is not a single InnerCap word in the entire book—HotMail becomes hotmail (and becomes the "Kleenex" (or, universal brand name) of email), and the quoted emails are largely devoid of the arcana (drek) that generally accompanies email in printed form: the smileys, the headers, etc. The only concession is the use of lines beginning with > for quoted emails within emails. Even the font used for email is blessedly humane—no Courier or Monaco or somesuch monstrosity. The word "Google" (initial cap) is used, and used as a verb. There are numerous details and plot twists that turn on some bit of high technology without alienating the general reader. All of which reminding us that this is a real medium we're using.
But what clinches the value of the book for me is the protagonist's humanity. I was expecting less, from the reknowned cyberpunk author. I was expecting genre fiction—in the negative sense, where everyone is a motive and a snarl and nothing else. Cayce spends a good part of the book just trying to get some sleep, and reaching out to her friends who are all elsewhere, via email and cell phone (she's an international traveller, to say the least, and the book's prismatic perspective on some of the great cities is enticing). Who can't relate to this chronic sleeplessness? And, departing from evandra, I find Cayce's allergy to trademarks amidst an especially trademarked world to be spot-on: she's like the countless Americans who, via sarcasm and jade, hold themselves above pop culture while still immersing themselves deeply in it. it reminds me of Murakami, this fictional milieu at the dream-edge of a familiar world, the parameters tweaked but the cosmos still intact.
And the footage. . . How long before someone actually does that?