There are three types of dashboards.  Outlined below are descriptions of each type.

Private - This is a dashboard that is private to your user. No other user in your business is able to see or modify this dashboard.

Shared - These dashboards are created by an individual user but are shared among all the users in the business. Anyone in that business can access or modify that dashboard.

System - This dashboard is created internally and is available to all users. You are not able to edit or delete system dashboards in any way.