In order to browse the Information Workbench there is no need to log in. There is a default profile that is loaded when no user has logged in, so that the information on each entity is displayed according a common profile.
If a user wants to change the way the information is shown, for example the collection of widgets used or their position, then it is necessary to be logged in, and therefore registered with a user account. This is also necessary in order to add information to the repository. In order to log in and/or register one needs only to click on the "Log in/Register" link in the head toolbar in any page of any entry. This will redirect the user to a log in/registration page. After logging in or registering, the user is redirected to the page that was being shown before logging in/registering.
To summarize, if browsing is the only task to do, there is no need to register or log in, but if there is a need to change anything in the workbench or to add information to it, the user has to be registered and needs to log in.