Aircell says that its Gogo service has had 1,000,000 users and now averages 100,000 users per week: I queried the company's PR firm, and had confirmed that this is sessions, not users. Aircell hasn't disclosed total unique users, any revenue figures, paid v. free sessions, airline-by-airline breakdowns, average revenue per paid session, or any numbers that the privately held firm could conceivably use to convince me or anyone in the flight industry that the service should be measured a success.
Don't get me wrong. I have no problem with the idea of a ramp-up time for routine travelers to get accustomed to the availability of in-flight Internet. Delta is well along its goal of putting Wi-Fi in its entire mainline fleet, but a traveler can't take any flight (although they can take certain routes) with assurance that Wi-Fi will be available.
As with Boeing's Connexion, I've always thought that you can't just make Wi-Fi in planes available; you have to make it predictably and routinely available, after which the real usage patterns emerge. Virgin America and Airtran have full fleet coverage, but the airlines are tiny and small, respectively, and have some loyalty but don't own their passengers in a way that the biggest airlines do.
I'd love for in-flight Internet to be a rousing success, because I so like the option to use it, and think it's a great tool for time-shifting work back into travel (instead of on either end), and for entertainment. But I'm not seeing any compelling statistics yet.