A federal judge ruled this month that a commercial plagiarism-detection tool popular among professors does not violate the copyright of students, even though it stores digital copies of their essays in the database that the company uses to check works for academic dishonesty. The decision also has wider implications for other digital services, such as Google's effort to scan books in major libraries and add them to its index for search purposes.

The lawyer for the students who sued the company said he plans to appeal.