A further discussion on Price's (Price, 2007) findings that students in online courses (at least that specific course at the OU) not only expect academic support from their tutors, but also emotional support (motivation, leadership, friendship).
I think that OU courses are structured according to constructivist principles. Constructivism implies the need to promote discovery, dialog, interaction, contextualisation and reflection, rather than delivery of content and information (Cooner, 2005). This means that the role of the tutor is less focused on delivery of content, but on a range of other tasks, dubbed "e-moderating" tasks (Salmon, 2004).
|E-moderating scheme (based on Salmon, 2004)|
In my opinion the main role of the tutor is to help students making their way through the course. For some people, occasional feedback on forum posts and assignments is sufficient, others may need more regular feedback or reassuring/ motivational messages. Ideally a tutor can gradually leave tasks to the group, such as responding to questions, praising others' postings, weaving and summarizing, taking a backseat position and filling the gaps where necessary.
I don't think the absence of "paralinguistic" clues is a big barrier to effective communication online ,although it took me some time to adapt to the language and customs of online communication. In particular, it's important to express your thoughts clearly, including how you feel about them, where necessary. Apart from that, I would argue that the lack of non-verbal communication can as much mean an advantage as a disadvantage, since this communication not always clarifies, but also obscures the meaning.