The primary focus of self-help groups is to provide emotional and practical support and an exchange of information. Such groups use participatory processes to provide opportunities for people to share knowledge, common experiences, and problems. Through their participation, members help themselves and others by gaining knowledge and information, and by obtaining and providing emotional and practical support. These groups have been particularly useful in helping people with chronic health conditions and physical and mental disabilities. Traumatic life events such as death and divorce are also the basis for groups. Self-help groups are voluntary, and they are mostly led by members. Generally, groups meet on a regular basis, are open to new members, and do not cost money to join. Traditionally, self-help groups have been in-person meetings, but recently Internet self-help groups have become popular.