The Harvard Wikis automatically save drafts at regular intervals while you are editing a page or a blog post. If something happens while you are working, you can come back later and pick up where you left off. Only one draft for a page of blog post can exist at any one time.
You can see the last time a draft was saved in the bottom right of the screen, below the "Save" button. Drafts are saved automatically every 30 seconds. You can see the last time a draft was saved in the bottom right of the edit screen.