The service is targeted at family/children and works well. Narrowing down the degrees of freedom (artwork in a consistent style, simple page layout [image + big font text]) makes it easy to create and share professional looking stories. You can invite others to collaborate with you as well.
Maybe the biggest application of this service is in education? There is a business presentation version of this application possible as well. Replace the image bank with non-cheesy useful presentation images (you only need a few hundred to cover most business presentations) and you have an alternative template to the PowerPoint bullet points. "Ayne can make Presentation Zen-style presentations"). Cutting the available slideware tools to the minimum helps focus the presentation design amateur on the story.
My first creation can be found here.