There are many definitions of digital storytelling. For me, a digital story is a story that is told using digital elements like still images, text, video, music, audio and is presented via software or a web application. As a writer and teacher, I find myself entranced with the possibilities inherent in such applications, which make it accessible for kids to tap into their own stories and present them to an audience.
One of my favourite web apps is Storybird. It's truly easy to use, and provides access to images created by illustrators. There's lots of support and it's fun. I wrote about it on my blog last year.