MPPC stands for Motion Picture Patents Company, also known as the Edison Trust, also known as the First Oligopoly.
The MPPC was a trust of all the major film companies (Edison, Biograph, Vitagraph, Essanay, Selig, Lubin, Kalem, American Star, American Pathé), the leading distributor (George Kleine) and the biggest supplier of raw film, Eastman Kodak.
At the time of the formation of the MPPC, Thomas Edison owned most of the major patents relating to motion pictures, especially that for raw film. The MPPC vigorously enforced its patents, constantly bringing suits and receiving injunctions against independent filmmakers. Many filmmakers responded by moving their operations to Hollywood, whose distance from Edison's home base of New Jersey made it more difficult for the MPPC to enforce its patents. Also, the proximity of Southern California to Mexico was convenient for Hollywood filmmakers; word that MPPC agents were traveling to California would usually precede the agents' arrival, allowing the filmmakers to flee to Mexico. [Southern California was also chosen because of its beautiful year-round weather.]
The reasons for its decline are manifold. The most important ones are the misjudgement of consumer interest and the quick rise of the so-called Independents, who later became the Second Oligopoly. There were also U.S. Supreme Court decisions, in particular one in 1912, which cancelled the patent on raw film, and a second in 1915, which cancelled all MPPC patents. The Sherman Antitrust Act in 1917 ended the oligopoly, but by then, the MPPC was already defeated.