Another Web 2.0 application suite, Versionate, joins Google Docs, pbWiki, Social Text and Confluence in challenging Microsoft's Sharepoint in the collaboration area.

This document-driven wiki-like service accepts uploads of office docs, PDFs, images, (but not PPT files, yet) over SSL connections to create wiki-like editable pages, organized in folders, with version, group and access controls. There's 500MB of storage with the entry-level free account, plus thirty-day trials for more capacious accounts reaching to 20GB at the $2/user-month level. All accounts give you full exports as well as imports for easy migration of your documents, another major advantage for users.

For more details go to http://www.versionate.com/

You may consider using this for ePortfolios; learners could set up their own Versionate and invite you as their instructor/tutor/teacher/professor...