For the past 6 months, or possibly more, I have been fighting and advocating for a Social Network. We looked at all the avenues - open source, internally hosted, externally hosted, etc. etc. We tried them every which way - yet none were perfect. Yet I keep advocating for them. Finally someone asked me - Why? Why do we want to spend effort on this? What does this do that Moodle can't do?
So I had to take a step back. Was I doing this - just to do it? Was I seduced by the "latest and greatest" in technology? I mean The Office even made a jab at having a "social network" for paper buying!
So I looked at our current situation and what a Social Network could add. Currently we use primarily BlackBoard Vista and have a Moodle Server. All of the BB Vista courses are actual courses. They are all locked down by classroom participant and discussions are instructor driven. One of the issues I have always had with online classes is the lack of personal connectedness between classmates. I miss the after class discussions on the wall outside of class. BB Vista & Moodle are so "course" oriented" it is hard to "force" them to be something else - possible, but hard.
So what can a Social Network add or change? I think the main thing is that it is user centered - not course centered. You are a Student who belongs to several different groups, rather than having a Course you happen to be a student in.
I am even willing to bet my thesis on it - can you say topic change!