In 2002, the number of wireless handheld
devices reached one billion. By 2006, that
number had doubled, and by December
2010, it had reached five billion (see www.
itu.int/ITU-D/ict/statistics). Although this exponential
growth will eventually slow down, given
that there are seven billion people on the planet,
in some countries, the number of mobile phones
is more than the total population—the adoption
rate is more than 100 percent.