You can use e-mail to respond to day-to-day questions and concerns students may have. If they missed class, they can e-mail you or a classmate for an update and the next day's assignment. If they're working on an assignment and have a question they can e-mail you for a response. If you're looking for a feedback about the class, they can e-mail a midterm evaluation and suggestions for improvement. If they're drafting and are looking for some initial feedback they can e-mail their draft to you with their concern. This last suggestion is often quite useful. Students can ask you questions while they're drafting, rather that only after the final draft has been completed. It can help teachers get more involved in the actual writing process, rather than just the final product. But again, temper all of these possibilities with logistical concerns to make sure you're using e-mail effectively and efficiently. If you don't want students e-mailing you a draft accompanied by, "Can you look this over and tell me what to do to get an 'A'", set clear guidelines for what type of feedback you'll provide and what students role will be. Should they send specific questions along with the draft?