When students read a book, they usually annotate important words on the text. Students may miss some important information while reading the book. If someone can remind them the potential important annotations, students might get better academic performance later in terms of having better marks for written exams, quizzes, and other learning activities. This research implements an online platform which can help students annotate reading activities with different ways. The online platform can also give students annotation suggestions according their annotation behaviours. On the other hand, teachers can use this platform to review students' annotations in order to discover students' potential learning problems. The platform can also help teachers cluster students into different groups according to their annotation behavious. Besides explaining and demonstrating the platform with examples, this research also designs an experiment plan for evaluating the system in the future.