"Jobs-To-Be-Done Theory" is an innovative concept put forward by the business community in recent years. This paper attempts to clarify the meaning of this concept and the similarities and differences between this concept and the concept of "task" in information behavior studies. At the end of the paper, the author urges researchers who study people information behaviors should strengthen the contexts of information needs and seeking behaviors. Researchers should apply "Jobs-To-Be-Done Theory" on studies of library user’s behaviors. For example, what are users trying to accomplish with a book (or information) in the library? By applying this theory, maybe libraries can find an innovation way to library services.