Joining or leaving a community is voluntary. We might not want to leave a good community but there is no obligation. Communities are made up of individuals and families who can afford to be there. Sometimes I hear Seekers described as family with family also meant in a metaphorical feel-good way. There is a sense of a little more obligation in the word family, and a little more sense of tribe.
Family has little more sense of boundaries and emotional ties.
It is a more parochial word. Seekers has some features that are not like community and family. In the standards for membership, in our strong commitments to inward and outward journeys, in our emphases on gifts and callings, stewardship, and in the ways worship lures us toward transcendence, we carry several truths that qualify the concept of community. This makes me feel better because one of my discomforts with the word community is that it is used a lot by the institutional church in the context of evangelism defined as membership growth. It is a very weak word in that context, having a feel of avoiding conflict and personal challenge.