RESPOND. Respond to email you receive. If you don't, the sender will assume (a) you didn't get it or (b) you don't want to respond. Remember that you're invisible to the writer. You're saying "I'm here" when you respond. If possible, reply immediately after receiving a message. If time doesn't allow for a full response, send a quick one-liner: "I'll reply in the next 12 hours." Reply within 12 to 24 hours of receiving a message. This is called "grounding," and in the virtual classroom, grounding is essential.