The socket seekers heads an article about the need for travelers to find juice, not just Internet service: Yes, people are power mad in airports as they carry more devices they need recharging before and between flights. Used to be that you'd see one or two laptop owners near convenient plugs. Now, the well-equipped traveler brings a power strip with them to make friends. (Hey, now that spawns a lot of new pick-up--or plug-in--lines.) There's now a connection between the increased use of Wi-Fi and the corresponding pre-flight battery drain.
This New York Times article notes the cost of adding outlets during construction--about $150 to $200 a pop, commensurate with in-building wiring--but that it costs thousands to add electrical sockets after a terminal is built. Some airports are getting clever, such as Chattanooga, pulling pay phones to put in electrical circuits.
The article also notes that travelers don't make too much of a fuss about outlets, because they're not sure they are allowed to use them; they generally are, apparently. I recall years ago that I was a bit nervous to plug in, because outlets were sometimes embedded in the floor for cleaners to use.