As reported by O’Reilly Radar, Fon is giving away free wifi routers. The “catch”:  In exchange for securely sharing a slice of your bandwidth with other members of the Fon network, you get either free access to other Fon network access points, or a share of the revenue Fon charges to paying users.  It’s a neat idea.

FON, the community WiFi-sharing startup, is giving away wireless routers to new members (Foneros). The routers are very small and portable — perfect for travelers. Out of the box it supports broadcasting two SSIDs: a protected one for your home and a public one for your fellow Foneros.

As I explained in my first Radar post about FON:

Most members (aka Foneros) “share their wireless Internet access at home and, in return, enjoy free WiFi wherever they find another Fonero’s Access Point”, these are known as Linuses. Aliens do not share their WiFi and are charged for using the FON network. Bills do not take advantage of the free roaming WiFi and instead get a cut of the fees that Aliens pay to use their WiFi. This could subsidize the cost of your WiFi if your business or home is in a heavily trafficked part of town.

Since you can throttle how much you share there’s not much to lose with trying it out.