Reaching 4.6 billion at the end of 2009, the number of cell phone subscriptions across the globe will hit 5 billion sometime in 2010, according to the International Telecommunication Union (ITU). The explosion in cell phone use has been driven not only by developed countries, but by developing nations hungry for services like mobile banking and health care.
and 1B mobile broadband subscriptions. Wow. Definitely a good time to be developing mobile apps.