One of Miller's strengths in the drama is how he is able to demonstrate that the trials in Salem were motivated by personal gain and political advancement. This can be seen in specific characters' motivations in initiating and continuing the trials. Reverend Parris is responsible for advancing the trials in the manner he does. He understands that as long as Salem is a swirl of confusion and fear in which the trials increase in ferocity and frequency, his position of power is evident. He benefits directly from more trials, as people look to him as a source of guidance and thus his power increases.
Thomas Putnam benefits in a similar manner with the trials. As more people are accused, they are forced to sell off their land ownings for a fraction of the value. Putnam pays this small price and then reassesses the land based on its original value, ensuring a good profit for himself. At the same time, his control of the Salem land percentage increases. For him, the trial is an opportunity to increase his political and economic advancement. It is to this end that Corey suggests through his informant that Putnam launches accusations at individuals for personal gain.
Naturally, Abigail would be a character who stands to gain much in her initiation of the trials. For Abigail, the trials are an opportunity to "eliminate" competition, or people that have made her life difficult. In particular, Abigail understands that if she is able to accuse Elizabeth Proctor and imprison her through bearing false witness, John Proctor would be hers to covet. The trials allow Abby to become someone important, of merit, in Salem. In this, Abby greatly benefits from initiating the trials in The Crucible.