This document discusses different types of groups and communities that social workers may engage with. It describes open groups that have changing membership and closed groups with fixed membership. Treatment groups focus on interactions between members to provide feedback and learning. Task groups work together on specific projects to meet client, organizational, or community needs. Examples include forums, committees, work teams, and social action groups. Self-help groups are informal associations that empower members to collectively improve living conditions through activities like microfinance. Joint liability groups are credit-oriented groups formed to obtain loans from banks.