This Storybird.com site is not for the birds!
If you are an elementary librarian, you will want to check out the latest in digital storytelling. Middle school and high school educators may be able to use this with some creativity also.
This is one example of what will replace the 'ole paper and crayon pencil paradigm as soon as schools have the technology connection to take advantage of these web 2.0 tools.
Still in its beta format, Storybird has great potential. I wish they had a search option for pictures tagged by keywords, but until then you'll have to search by "theme".
As with any assignment creation, it is imperative to embed higher-level thought. I see this tool effective for those who are fostering creative writing, but with some effort, teachers could promote higher level thought within the authorship. The assignment could include talking animals (personification, 1st person lessons) where the animal had to report the impact of something in history on their environment. A child main character could talk to the reader about a historical event that happened in their town. Etc.
Take the Storybird tour below and see what you think. This is not as flexible as Microsoft's product but it is simple. I like the "invite a friend" collaboration option.