The Tipping Point/Gladwell 173-182

174 small close-knit groups have the power to magnify the epidemic potential of a message or idea.

175 the Rule of 150

176 intellectual capacity—our ability to process raw information.

179 The figure of 150 seems to represent the maximum number of individuals with whom we can have a genuinely social relationship, the kind of relationship that goes with knowing who they are and how they relate to us.

181 Keeping things under 150 just seems to be the best and the most efficient way to manage a group of people.

182 The Rule of 150 suggests that the size of a group is another one of those subtle contextual factors that can make a big difference.
…we have to keep groups below the 150 Tipping Point.