Revenge was certainly a chief motive for the witch hunt. The years leading up to the witch hunt were ripe with feuds (notice how Proctor and Parris dislike each other - since Parris arrived Proctor has all but ceased attending church, mainly because Parris is greedy and worried about possessions rather than a religion), disputes (recall how Putnam accuses Proctor of taking wood from his land. Giles, though, steps in and reminds him how his grandfather had a habit of willing land that he did not own), and old resentments (recall how Putnam is angry that his man for minister did not get selected or how Tituba holds a grudge against Parris for capturing and enslaving her during his time in the Barbados).
All of these factors are building up in the community. Then throw in the strict Puritan religious code where children are to be silent and near invisible, where you have the \'elect\' (those who are predestined for heaven) and everyone else and you have the scenario that leads to the mass hysteria and general revenge of the witch hunt.
Note, however, that the witch-hunt years aren\'t devoted just to getting revenge. The girls begin to like the attention and power they gain from the trials. This becomes a factor for how long the trials go on. Really until Abigail oversteps her authority by implying that Judge Danforth is not out of the devil\'s reach, she was pretty much allowed to accuse at free will.
Well everyone thought that since the girls were accusing anyone they wanted, the community thought maybe we can get something from this. So they started accusing people who had done them wrong, and in this time of turmoil and confusion everyone believed everything that was being said.