Nokia source: revised global estimates: http://www.nokia.com/press/press-releases/showpressrelease?newsid=1393524
Nokia source: revised global estimates: http://www.nokia.com/press/press-releases/showpressrelease?newsid=1393524
A related article by Tomi T Ahonenthat explores the SMS component of baseline functionality: for example whilst every one of the 5 billion mobile phones offer text messaging (SMS) services the illiterate, illiterate children (too young to learn to write), and the ergonomically infirm (e.g. people with arthritis) are not be using text messaging. In addition multiple SIM card users may channel text messages and other data services through one SIM card and their voice calls through another. See: http://communities-dominate.blogs.com/brands/2010/02/portio-mobile-messaging-user-number-is-too-big-cant-be-4b-today-more-like-36b.html