Thanks @1L2P. @dirk has done a phenomenal job helping launch our PWYM Discourse community. As with LCL, we're interested in seeing how Discourse will work for our community vs. G+ due to the lack of persistence of G+ posts. For PWYM 2.0, we're using Discourse as the core community, but also encouraging people to organize groups where they feel most comfortable - PWYM Discourse, Facebook, G+, Twitter, elsewhere...
Our hypothesis is to a) encourage people to form communities where they are online, and b) be able to easily switch among groups. We hope to establish Discourse as the "hub" of the community, with "spokes" emanating to groups on other various social networks.
Your advice about starting with as few Categories as possible is great. We'll start there. PWYM may be a bit different from LCL in that we anticipate creating multiple course "pathways" in the future. So, we're currently deliberating how to structure top level categories. Do we create one called PWYM 2 as the top level, or create the top level categories by Activities? We'll continue to think on this and see how it goes for PWYM 2, hopefully to launch very soon.
We also added some structure to the G+ group to see if it is helpful to PWYM 2.0 participants that choose to use G+: