We will be starting accelerated courses this summer, so I am interested in this topic as well. I have taught online courses in a 12-week format since 2003, and we have had good results with retention by focusing on relationship building and staying connected to our students with as much interaction as possible. We are hoping the accelerated versions of our courses will also work well for our students.

There are also time zones to consider when teaching online classes that make it more difficult to "draw the lines" unless you are very clear in setting the expectation up front and identifying whether the deadline is based on Eastern time, etc.