[walterbell]

Tomi Ahonen has written at length about SMS vs other channels, http://communities-dominate.blogs.com/brands/2015/06/mobile-...

  DIGITAL REACH IN 2015 OF ALL HUMANS ALIVE (7.2B PEOPLE)

  iPhone . . . . . . . . . .  300 million download iPhone apps (4% of humans)
  Tablets (any OS) . . . . .  600 million owners (8% of humans)
  Whatsapp . . . . . .  . . . 900 million active users (12% of humans)

  Facebook on mobile . . . .  1,200 million (1.2 B) mobile users (17% of humans)
  Skype . . . . . . . . .. .  1,200 million (1.2 B) on any tech (17% of humans)
  Android . . . . . . . . . . 1,300 million (1.3 B) download Android apps (18% of humans)
  Facebook (all tech) . . . . 1,400 million (1.4 B) active users (19% of humans)

  PCs (all types) . . .  . .  1,500 million (1.5 B) in use (21% of humans)
  eMail on mobile . . . . . . 2,200 million (2.2 B) active users (31% of humans)
  Mobile internet . . . . . . 2,200 million (2.2 B) active users (31% of humans)
  eMail on any tech . . . . . 2,500 million (2.5 B) active users (35% of humans)

  Internet on any tech . . .  3,000 million (3.0 B) active users (42% of humans)

  SMS text messaging . . .  . 5,400 million active users (75% of humans)

  Table by TomiAhonen Consulting, June 2015, data collected from multiple public sources 2014-2015.