In the design and development phase, you will be describing learning objectives and outcomes for the course in a way that is approachable for the learners and then defining specific activities and tasks that fulfill those objectives and outcomes.
Online courses require you to maintain a social presence because it is important that the learners see the faculty as real human beings. Similarly, this notion must be echoed in the online learning environment itself — learners should feel like they are part of a community where they can openly initiate and participate in discussions.
Why is this different online?
In face-to-face courses, the instructor can physically provide important instructional materials and verbally direct and redirect learners through various learning activities. Such moderated guidance is not available in the same manner online, where learning is more exploratory by nature. In most cases, learners are accessing course content and interacting with learning activities asynchronously. A great deal of care must be given to the creation, organization, placement, and support of course content. The easier it is for learners to locate and engage with learning activities, the more mental energy they will have to focus on the content.