Santa Clara, Calif. -- Chegg, the Santa Clara-based operator of an online textbook rental service, said on Wednesday it has acquired Pasadena-based Cramster, developer of a social platform providing online homework help. Financial terms of the deal were not disclosed. Chegg said the acquisition adds to its textbook rental and course planning services. Cramster's online study community is comprised of college and high school students, teachers, professors, parents and subject matter experts who contribute information in nearly all subjects to various study resources. Founded in 2002 by Aaron Hawkey, Robert Angarita and Kaveh Golabi, the site currently boasts more than 1 million members.