You can control who has access to your portfolios. By default, only you can see your portfolios. You can share your portfolios with the public, registered people, your institution(s), groups, or your friends. You can assign access to individual groups or people by using the options under "Share with" → "Search for...".
Access dates can be set, allowing you to make your portfolios available for a specified period such as a course year, a project timeline, or even for one day only. All dates are optional. Individual people can be granted access by multiple access rules.
Example: Nigel is in the group "The Coolpeople's Club". If you allow him to access your page today and allow "The Coolpeople's Club" to access your page tomorrow, he will be able to access the page on both days.