Groups enable you to do two things in Easy Insight. They enable you to restrict user access to particular data sources, dashboards, or reports. They also enable you to consolidate a set of users for purposes of scheduling emails--instead of repeatedly selecting the same users for a particular email delivery, you can just select a group as the email recipient and add/remove users from that group as necessary.
You can add, edit, or remove groups on your account from the Groups page under Account Settings:
You can create a group by clicking on the Add Group button or edit a group by clicking on its name in the table.
For each user you include in a group, you can set them with different privilege levels:
You can add data sources, reports, and dashboards to a group: