Write.fm

Write.fm is a site for creating and sharing documents.  You can even upload a file to the document, so another way to share and discuss a picture, article, cartoon, etc.  The site also allows you to EASILY create your own URL.  This would be a great way as an educator to go paperless if your school has not provided a way for you to do so.  Like most of these sites, I am sure that whatever you create becomes their property.