With more and more gadgets supporting wifi connections, it's more and more desirable to have open wireless access everywhere. Most people are hesitant to leave their wi-fi network open to strangers for a variety of reasons: you don't want to have your traffic sniffed, have your computers hacked, or have illegal materials transmitted over your network.
When I was in Holland, a
friend showed me really clever gadget that allows for reciprocal "I'll let you use mine if you let me use yours"-style sharing: Fon wifi.
You replace your existing wi-fi router with Fon's router ($40-50), and the gadget creates two wi-fi networks: a private (WPA encrypted) one for you to use, and a public one that shares your internet connection with any other Fon customers. (They have to log in to get access.) You can choose to benefit from this either by being paid, or by receiving reciprocal free internet access through anyone other customer's Fon.
Since I'd never heard of Fon, I assumed it was just a European thing. Wrong! There are a few dozen Fons in the neighborhood. You too can check
their map and see where they have customers. I can't figure out how they have dozens of people using this in Seattle without my having heard anything about it.
I'm tempted to sign up, but held back by two things: I've just got my wi-fi setup working smoothly, and I've got a relatively slow DSL connection that I'm not dying to share. Hrrmmm.