Well, it's unfortunately trying to be everything... but most of the NSS volunteer leadership seems to date back to the L5 society days, though the executive leadership seems to have closer ties to government/industry space than the L5 idealism. The other big grassroots group is the Planetary Society, which seems to have settled on robotic and human Mars exploration (along with the smaller Mars Society). The stated near-term NSS goals are perhaps more mundane, but one would think also more relevant to society here on Earth - low-cost access to space, improvements in space solar power, a scientific lunar base, etc.