The NY Times on “push to talk” services…

IT’S weird: even as communications technologies become more advanced, the older, simpler methods sometimes seem to become more attractive. Video chats over the Internet may be free and easy, but the masses stick to the humble telephone. Cellphones can transmit both voice and photos, but millions of people prefer to fire off short, painstakingly typed text messages. What’s next, a comeback tour for smoke signals?
The popularity of Nextel, whose cellphones double as national walkie-talkies linking its customers, proves the point. Remember walkie-talkies? To speak, you have to hold down a button on the side of the phone. Only one of you can talk at a time. You can say “Over!” after each utterance (although these days, a little beep conveys the same point).
This old-fashioned idea, called Direct Connect, helped Nextel become a major cellular player, and accounts for its preposterously low customer-turnover rate (less than 2 percent a year, Nextel says). All that success couldn’t help but attract the attention of bigger players, who within the last few months have introduced their own rival walkie-talkie services: Verizon Push to Talk and Sprint Ready Link
(full story)