I think many in the Moodle community are interested in social network analysis, but these projects do come and go. The issue I see with Forum Graph is that it only includes forum interactions, when learners can also interact in wiki, database, workshop, etc.
We are definitely interested in more than "what/where/when" log analysis. The Community of Inquiry indicators we have been building for Moodle include things like the number of peer connections, and I've been looking at indicators like network centrality and density. I think a SNA graph would be a helpful addition to Moodle, but it would be descriptive only. I am leery of providing descriptive visualizations without some analysis to back up how useful they are in predicting the outcomes of a given program.
For a general overview of Moodle Learning Analytics, start here: https://moodle.org/course/view.php?id=17233§ion=1
I have been struggling with how to organize the page, particularly how to balance information for new visitors vs. long-term participants.