"What I find myself wanting is some means of online social interaction that might begin to replicate the vastly superior learning experience of sitting down with a patient, friendly musician willing to share a few licks and tips."As I mentioned in a comment on his post, I think this is something the 4600-ish people in 43 Things who are also learning to play guitar could benefit from too. The "network" that has formed around the learning goal there isn't so much about helping each other achieve the goal -- it seems to be more focused on helping people decide whether to pursue it in the first place, and how to get started. Once they've adopted or rejected the goal, very few return to participate in any meaningful way. It's like the assumption is that once you've started, the learning will take place in isolation (or at least elsewhere).
Update: Only obliquely related through the guitar theme, but I enjoyed this post from Bill Kerr about how offical education will be (or is being) left behind as people realize they can learn more about what they care about on their own, seeking out other people and resources as necessary. He was bouncing off of a video of a young guy playing a ripping version of Canon in D on his electric guitar, which has been viewed over 7 million times on YouTube...talk about reach.