An online community is an interactive group of people joined together by a common interest. It's also one of the most powerful tools a marketer can deploy for customer retention, word of mouth, and customer insight. To host a successful community, think of it as you would product development: Start by focusing on objectives, chart a road map, assemble the right team, and plan to be flexible. Then build your success by launching the community with the backing of your most enthusiastic customers and staying engaged as the community grows. Above all, remember that control is in the hands of the members, so put their needs first, build trust, and become an active part of the community.