The Dink Network

As someone who knows a few Jehovah's witnesses, I can say most of the stuff Phoenix quoted is very well-founded, for example, the mental oppression part. Members are discouraged from being involved with people who don't belong to the faction, even being in the school soccer club or involved in after school activities is shunned at. If your entire circle of friends consists of Jehovah's witnesses and you resign/get kicked out, your old friends won't so much as say hi to you on the street.

As for the reasons of "disfellowshipment", the bad stuff you mention involves things like accepting blood transfusions, living in a relationship without being married, or just openly disagreeing with their interpretation of the bible.