One of the greatest aspects of JW mind control is the very real threat of expulsion and shunning.
This is far more significant than excommunication, as practiced by various other churches. JW explusion and shunning is not merely being cut off from the church. It ends ties with friends and family, outside the sphere of church activities. For example, if Bob Roberts is excommunicated from the Catholic Church, Bob remains a full member of the Roberts family. However, if Brother Brown is disfellowshipped from the JWs, he will also cease (in all reality) to be a full member of the Brown family, if they are JWs. He will be treated worse than a convicted criminal or a stranger and he may even be treated as worse than dead.)
This threat of expulsion and shunning translates into spiritual and emotional blackmail, as the cult member believes his eternal salvation is linked to the organization. Moreover, his very social structure and loved family members are dangled before him as an inducement to remain in the cult. The impact this has on the mind of the cult member is hard to overestimate.
This is not a feature of most Christian denominations. It is unique to high-control, authoritarian groups and to destructive cults.
-LWT