Having a social presence in your unit through different communication channels means that you can introduce yourself and also clearly articulate your expectations of students during the course of the unit.
the standard and format of work they need to complete.
how and when you will participate online
response times for feedback on their questions and assessment
Netiquette is also a helpful way to help students communicate more effectively and ensure students understand their roles and responsibilities and your expectations. For more information refer to netiquette and guidelines (Source:Teaching Online Course).