Some individuals, who are regarded as role-models, can persuade others to follow their example. This form of persuasion might not be consciously intended, but can nonetheless be effective: celebrity attracts imitators.
Well-known people can lend their names to good causes. Princess Diana was a prominent example, as reported by the BBC: Diana’s Charities.
Less well-regarded people can attract support by mentioning popular role-models who endorse their cause.
People have an instinctive desire to be part of a social group. Some people might join a religious organisation mainly because of respect and admiration for those who already belong.