One of the weirder applications of RFID was to be controlling a hot spot useage. The RFID chip gets imbedded in the coffee cup and contains some kind of magic cookie. The customer registers when they buy the coffee, which gives them xx minutes of Wi-Fi use. When they go for refills, the pass the coffee cup near some kind of reader which renews the usage limit. As long as they're in the shop guzzling coffee, their wi-fi connection stays alive. When done, they just toss the coffee cup. I haven't seen anyone actually doing this, or selling the technology, but it is possible.
The free Windoze version of Ntop is limited to capturing 1000 packets. To get full functionality under Windoze, you must either compile your own from source, or contribute 50 Euros to the development effort.