New markets are finally opening up for plagiarism-detection software, a mainstay of academia that has struggled to expand its reach beyond term papers. The scandal-plagued newspaper industry is considering whether to adopt the technology to crack down on copycats, while the New York Police Department is testing it as an investigative tool. But experts say the biggest potential market might be the publishing industry, which one day may find itself coping with the same kind of piracy that bedevils movie makers and music producers.