Rackets are businesses not owned by La Mafia, but rather that pay tribute to the cartel or share their profits with them. In exchange for this, La Mafia "protects" the business... usually from La Mafia. In other words, either they pay or they get wiped out. Rackets could also be owned by associates of La Mafia, in which case it is voluntary and the business receives protection and has opposition eliminated, while La Mafia either gets a share or free resources.