Ok, so far I barely started the analysis stage, the first part I have found confusing. The question is "1.Provide a brief overview of the online community, including its purpose, function and goals." I'm getting confused between the purposes and functions of the online community. This particular case study in particular was the Victoria Heights College one.
I'm not familiar with that case study in particular, but anyway:
Well the purpose of the online community, you want to think about questions such as: Why does it exist? Why does Victoria Heights College need an online community? What are they doing with it (for example, it might be so that parents can receive information from the school etc.)
Functions of the online community: What can the online community do? What does the online community have? What are the features of the online community? (for example, it might have a forum feature to allow users to hold discussions or there might be a feature where there is a webpage that has information about the school's contact details) - in general, you'd probably want to mention one of these five things:
http://www.vcaa.vic.edu.au/vcaa/correspondence/bulletins/2010/July/vce_study.html#H3N10050.
I guess you could also think of purposes as being 'why' and the function of being 'how' that is achieved. Of course, the question only states 'brief overview', so you wouldn't be going into too much detail at all beyond simply mentioning things really.