|Cover of Philip Ball's 2004 Critical Mass, showing a critical mass of what looks like either a mass exodus, mass pilgrimage, or large column of troops marching to war. |
The term seem to have come into popularity during the 2003 talks on the "physics of society" by English chemist and physicist Philip Ball and follow-up 2004 book.  The following 2010 quote by Indian business theorist Vineet Nayar indicates an incorporated utilization of the critical mass theory: 
“When a critical mass of employees [activate] (usually, 5 or 10 percent is all you need), throughout the company, it creates a kind of fusion – a coming together of the human particles in the corporate molecule that releases a massive amount of energy.”
Critical mass can be defined in the sense of “attracting attention and anticipating influence.” 
● Muller stability ratio
● Muller dispersion force
1. (a) Ball, Philip. (2003). “The Physics of Society”, A talk Delivered at the London School of Economics, March.
(b) Ball, Philip. (2004). Critical Mass - How One Thing Leads to Another (social physics, social mechanics, pg. 58; free will, pgs. 71-72, Buckle, 65-69, 205). New York: Farrar, Straus and Giroux.
2. Nayar, Vineet. (2010). Employees First, Customers Second (quote, pg. 165; energy, 11+ pgs.). Harvard Business Books.
3. Walker, James W. and Thomson, Andrew S. (2008). Critical Mass: the Emergence of Global Society (critical mass (def), pg. xvi). Wilfrid Laurier Univ. Press.
● Critical mass (sociodynamics) – Wikipedia.
● Critical mass (disambiguation) – Wikipedia.