IP-based (Internet Protocol) telephony is certain to overtake switched-circuit telephony. Skype leads in the number of Voice over IP (VoIP) users and certainly has a global reach. Mobile telephone handsets will eventually communicate via IP. Now, there are some handsets, notably from Nokia, that is WiFi and coming as WiMax, and which also have switched circuit capability. In addition, Nokia's 770, a Linux OS tablet for about US$350 and WiFi, shows the possibility of these devices becoming phones.