Reuter reports that Fon could move from grassroots to mainstream: Fon, so far, has build its tens of thousands of nodes mostly through individuals who obtain a router from them or flash an existing device with new firmware, and set up shop. Although some ISPs allow and some tolerate sharing a connection via Fon, only a few actively encourage it. This could change, Reuters reports, if a deal with BT goes through.
Under the deal, which BT and Fon wouldn't comment on for Reuters, BT would allow its millions of broadband users to share their networks with Fon, and BT's Fusion mobile callers--who can call over Wi-Fi or cell using UMA (unlicensed mobile access)--could access Fon's nodes to place calls. Fon claims 250,000 Foneros, but a smaller number of active nodes.
The Fusion plan would benefit from BT-broadband-backed Wi-Fi nodes because BT can separate VoIP packets on their side of the broadband connection, providing a higher-quality service than a company like Vonage, which must push VoIP packets over the broadband connection out to the Internet, over an unpredictable route.
The article claims that BT could push software to its routers to enable Fon, but I imagine that's an oversimplification--unless most BT broadband users also received a Wi-Fi router from BT, and it's a router that they can insert Fon software into.