The airport decided to unleash its service at no cost: Denver (DIA) is an interesting case, being one of a few early airports in which Wi-Fi was built by Nokia when it thought it might become a Wi-Fi infrastructure player. As I wrote in Nov. 2001 in a story in the New York Times, the airport had a fully functional system and couldn't find an operator. Nokia was, in fact, paying them a promised fee even though it wasn't providing access. The next summer, they were lit up.
None of the country's or world's largest airports offer free Wi-Fi, while many still large but second-tier airports charge nothing, like Las Vegas, Sacramento, Portland (Ore.), and Phoenix. Denver was seeing about 19,000 to 20,000 monthly sessions at a fee, and now sees 10 times that number--without really advertising the fact until today that service was available at no charge.
I don't see this as a trend--there are typically too many expenses and too many contracts involved in providing large-airport Wi-Fi for the costs to be subsidized. Denver may have chosen to go free as a competitive move against Salt Lake City, Dallas, Chicago, and Minneapolis to get passengers from those hubs. The airport's explanation is rather thin.
Glenn,
The Denver WiFi network was originally installed by AerZone/Softnet/Laptop Lane. The hardware chosen at that time was Nokia firewalls and 802.11b APs, all installed by Laptop Lane as a "proof of concept" for DIA. When Softnet folded AerZone and sold off Laptop Lane's assets in August of 2001, DIA essentially siezed the WiFi network as abandoned assets. They then contracted with AT&T to run the network there, who contracted it to Nokia to run it. Heck, Nokia really didn't have anything to do with it then either; they contracted with a third party to run the walled garden network for them. When Cingular merged with AT&T, the WiFi network was then picked up by Cingular from 2004 to 2005, when SBC and Wayport was brought in to run the network after AT&T's crew was pulled out.
Denver's network as a whole is different than the other airport networks I've dealt with. The people at DIA who run the network, I believe, consider the plant as an asset that they use to provide worth to their customers (i.e. Airlines).
It's much like how the Hotel markets have gone; where it's an amenity/cost center instead of a revenue generator. They provide not only consumer WiFi, but WiFi for the airlines for baggage check-in, free TV sync-ups, etc. If you have a choice that either you can fly thru St Louis, or Denver, with all things being the same, you may choose Denver now because it has free WiFi.