Ok, so they investigated computer simulations of three different models of communication within a population. Everyone talks to everyone else, special hub people who talk to lots of people, and everyone with equal number of connections. Then they sprinkled in special people who's opinions couldn't be changed, and let them talk.
Couple Questions:
How did they determine whether listening to someone influenced a persons opinion?
Seems likely that in a given population, a minority of committed individuals like this would naturally self segregate, possibly even leaving the population voluntarily.
Did they model the continual rotation of population? Even the luckiest individual is around to spread his/her opinion for 100 years.