Live Binders is a web tool that allows you to create an online binder with tabs and sub tabs. You can use this to share and annotate images, websites, google docs and more. This would be a good site to create an online portfolio for students and professionals.
This is a Binder about iPads that shows how LiveBinders can be used to share information through topics and sub topics.
http://livebinders.com/media/get/MTgyNTQ0
Live Binders