Is it possible to store a partly finished entry? (Question via email)

Yes, entries can be saved as un-published drafts. Use this functionality to periodically save your work as you go along, or to put away a partial entry for later completion. (But beware! Read on...)

To save your draft post, in the Options section at the top of the submission form for blog (and other content type) posts, un-checkmark Published before clicking Submit.

The post will be saved and accessible to you, but not visible to others on the site -- until you checkmark the Published option entry and re-submit the post.

Major caveat: Our current system provides no way to list your unpublished posts. In order to come back to your post later, make sure to make a Bookmark or Favorite (in your web browser) of the post page.