Profiles are an easy way to streamline the view of the portal for an individual or a group of users. When a module is unchecked within a profile, that module is removed from the toolbar. For example, if the portal will be used for internal employees and external customers, a Level 1 Administrator could disable the Personal area for customers (e.g., mail, personal calendars, documents, etc.) while allowing the internal employees to have access to mail, and all personal sections.
The combination of this function and workspace memberships provides a customized view/access for different audiences within the portal. There is no limitation on the number of profiles an administrator can create in a portal.