Sandstorm is a fantastic way to create web-based documents and share them with your workgroup or friends.
It supports a growing variety of open-source applications that allow you to collaborate in real time.
You can sign up for an account here.
Sandstorm provides an easy way to use a variety of open-source applications.
In each application, you create new documents called "grains" which can be shared with anyone by email.
This means that you can easily see who has access to documents.
For a full list of applications. see here