Dersdeo is a distance education support system. Lesson videos prepared by education staffs most of whom our teachers are planned according to students’ concentration span. Lesson videos of which length is from 5 minutes to 12 minutes have been classified in a way not to be used in Turkey. Specific videos have been prepared for each topic in the syllabus. As a result of this, students who want to review only a few topics have been provided to find immediately what they have been looking for.