That's interesting. I hadn't spotted that before, thanks.
If you are interested in flexible wireless sensor networks, have a look at TinyOS.
Folks are building 'motes' (small intelligent sensors) which form into ad-hoc wireless networks. This has been running for several years. TinyOS 2.0 came out in 2006.
It runs on a range of hardware including Atmel microcontrollers.
It uses a special programming language, nesC, so that the compiler can build tiny executables. TinyOS has a mesh wireless network stack.
AFAIK, a major problem is the hardware is expensive ($300+). (I think there is some military or government funding, and they probably don't think $300+ is expensive for a wireless sensor 'mote')
I've sometimes toyed with the idea of making motes using an Arduino and a cheap 2.4GHz radio.
GB