I came across an interesting question, while reading forum posts on the discussion group. Bronwyn Stuckey raised the issue of facilitation coming through public and private channels.
In the courses I have taught so far both channels are used. Public goes through forums, whereas private is either via Moodle's messenger or e-mail. Of course, blended courses offer the opportunity for a f2f support, which, however, is rarely taking place in online courses.
I would indulge into discussing the channels themselves. As already mentioned, the public channel is based on forums. I use two types of work facilitation forums - News Forum and I Need Help.
The former is set to give news and announcements. The participants can reply, but cannot have a discussion between themselves. The latter is the place where cries for help are posted, concerning technical difficulties or unclear tasks. I believe that this way of dealing with problems is quite efficient - it is very often the case that the post's author might get a reply from another participant on how to solve their problem. In such situations, I always leave a 'thank you' note. I think that this way my online presence is enhanced.
The private channel - Moodle's messenger or e-mail. Mostly private communication goes through the messenger. In the language courses, I use it to correct mistakes in forum posts: that usually takes some time. However, later on I have a clear record on mistakes and could easily see whether the person is working towards improvement. The next function is to praise and rarely to criticise. This one-to-one approach helps especially those who are shy, or simply not used to studying online.
Sometimes participants contact me via the messanger with a problem. If it is a single person issue - I reply, but advise them to use the 'I Need Help' forum, as the chances to get a faster response are higher. If several participants contact me with the same problem (which means that I have overlooked something in the course), I usually post my reply in the 'News Forum'.
I believe that being able to contact the teacher privately is of high importance, especially when the student finds him/herself in a completely new learning environment.