IV. Which digital technology has the highest penetration rate?

I think smartphone is the highest penetration rate. Smartphone has achieved 50 percent penetration of America customer market(R.A. 2012). In Australia, the population of mobile user achieve to 12.2 million at the end of 2012. http://www.economist.com/blogs/freeexchange/2012/04/general-purpose-technologies http://blog.marginmedia.com.au/Our-Blog/bid/81865/Smartphone-Use-in-Australia-The-Advantage-for-Marketers