If you're using NAV 2013 or a newer version and have multiple companies in your database (or multiple databases), you should consider using the System Indicator to easily identify which company you're logged in to.
While on the Role Center page, the company name is shown in multiple places such as the address bar at the top, and in the status bar at the bottom of the NAV window.
However, if you're drilling down or looking at a page that opens up in a new window, you will not be able to identify the company you're currently in. This can be a source of confusion for users working in 
multiple companies simultaneously (or frequently switching between companies) and for developers looking to test functionality in a multi-database environment. This issue is addressed by the System Indicator functionality.