According to sociologist Phil Bartle in What is Community? A Sociological Perspective [http://www.scn.org/cmp/whatcom.htm], "We can not see a whole community, we can not touch it, and we can not directly experience it. .. a community may come in one of many shapes, sizes, colours and locations, no two of which are alike... a community is not just the people who are in it. A community usually was already existing when all of its current residents were not yet born, and it will likely continue to exist when all of the people in it have left..."
And that is where the archivist comes in. One of our prime roles (and I would argue that it is our primary prime role) is to keep track of communities. Human beings are bound by their "humanness" and archivists retain evidence of that truth. We preserve, maintain, and provide access to man-made creations that show where the human race has been, which helps guide it to where it is going. With this evidence, users gain a greater understanding of themselves, others, and the communities in which they exist. They create new things and build upon past ideas. Our archives help sustain us and give us the knowledge we need to continue and grow civilization.
In addition to the human community, individuals exist in numerous other, smaller, communities. We have a certain nationality, we live in a certain territory, in a specific town. We are part of a certain profession. We share hobbies, ideas, and religions with others in intersecting communities. When we examine ourselves and consider our various communities, we evaluate ourselves. We have a purpose on this earth. We build communities to project and grow our identities. We seek "commonness" with others to secure our purpose and create written documentation to cement relationships and explain ourselves.
The archivist's role is to capture the multi-dimensional aspects of community. Repositories must seek to balance collections, to include documentation created by people from all different backgrounds -- from all different communities. Our collections should fairly show the diversity of individuals and their communities to present a comprehensive view of humans. Through the archivists' work, future generations can see what it meant to be human in a particular time and place -- how we functioned, how we thought, how we communicated, and how we changed. Archives show us how we got where we are today and that things are always morphing even though our "humanness" remains the same as it has always been.