Doug, I completed my profile a little so I guess that counts as an intro ;)
I only want to share some visions:
To maximize the number of teachers that would use this social network it should be integrated in Moodle.
One example is when adding an activity from Moodle, it could be searched and imported from MoodleNet directly without downloading it first.
But prior to this, if a teacher wants to add Moodlenet resources published from other teachers to their course it should first register their own site and at least share some basic info about the courses he/she is teaching, or better, share some resources.
Once registered MoodleNet could suggest adding as contacts teachers in their zone/language that teach the same levels and subjects.
Then it should suggest proactively new activities published from other teachers that you follow.
Let me know what you think!