Groups are where SyneMind becomes useful not only for individuals but also for groups of people - families, teams, or other sets of people who need to share content.
If your account level allows it, you can create a group and invite people to it. They need to pro-actively accept the invitation in order to become members.
When you create a group, you automatically become group admin with full rights, and you cannot change that - because, well, if you remove yourself as admin then nobody will be able to administrate that group anymore.
In the member management screen, you will be to able assign rights to the other member - and you can also make somebody else full admin; and yes, they will be able to demote you then - but that means that least one active admin will remain at all times.
Group members can be just members (can read content), editors (can also add or edit content), or group admins (can edit the group itself, and manage members).
Editors can share content into the group, making it easier to disseminate knowledge to "stakeholders" - from cooking recipes shared to the family, to onboarding documents needed by new team members in a company, to compliance documents that a body corporate needs to provide to owners, to... well, you get the picture.