Let’s face it, we all like to feel part of something. We all like to feel that we are reaching out to others of like mind (or interest). On some level this can be translated as "self interest" (even if all we get out of it is "satisfaction" or a "sense of community").
But this site shows that there is something even more important … BENEFITS! The community actually "feeds the needs" of its members! One of the things that Harley Davidson do well is make it clear that there are a whole range of EXPERIENTIAL benefits that come along with membership of their worldwide community.
The site nicely articulates "what you receive", "what you can earn", "what you can do" and "what you can use". Do you offer your community something of value? Is it clearly articulated?