How people's attention flows on the web
30 April 2011
Under 55 daily installations, friend behaviour was an instrumental part of the decision to install. Over 55 daily installations, and friend behaviour didn’t matter one jot.
The article is from October 2010 with the study referred to covering apps installed by the entire Facebook userbase during July / August 2007.
One implication is that popularity is not like an infectious disease and does not spread as such.