T-Mobile seems to be keeping its eye on the possibility that its Wi-Fi network may cannibalize potential cell revenue: Some say that Wi-Fi is a good draw for T-Mobile because customers may switch their cell phone service to T-Mobile so that they can get a single bill for cell and Wi-Fi. T-Mobile hasn't come out with any definitive plans for deploying a very high-speed upgrade to its cell network so it seems to be using Wi-Fi as the wireless broadband offering for its customers. Without a high-speed data service on its cell phone network, the Wi-Fi network isn't going to cannibalize the cellular service. Even if voice becomes popular on Wi-Fi networks, Wi-Fi won't be as ubiquitous as cellular.