"The Internet contains a lot of resources that teachers can access and use to prepare teaching materials." Such as lesson plans, rubrics, activities, worksheets, exercises, quizzes, which we could borrow from Internet source and make some changes according to the needs of our students. It saves time and diverses the form as well. Traditionally, the teacher provides handout to the students and they work on it. But with Internet, we can prepare some audio and even video to teach English, which is interesting and exciting to various levels of students. Even to me, as a professional English learner, I get excited while watching a video in class.
Of course, we can also find piles of authentic materials online, such as newspaper, magazines, updated posts, discussion forums, which functions as an authentic language environment to involve the students into a real English world. Internet helps extend the class time. Most students use Internet at home nowadays, they can discuss whatever they like online with their classmates or even someone they don't know. Their questions and doubts would be posted on teacher's blog so that we can see it and solve it.