Bubblin aims to bring superbooks to the world.
There doesn't seem a reason to limit our experience of reading e-books to what we had with physical books - a.k.a just lifeless text and images. Web has better and much powerful tools to create books that assist in reader learning. Books that help readers to grasp key concepts easily with the help of visual explanations and interactive contextual substance that wouldn't be possible without the web.
A lot of this thought has been explained in this excellent presentation on new mediums and new forms of art: Stop Drawing Dead Fish by Bret Victor. Bubblin is an effort to achieve a bit of that.
My aim with Bubblin is to create books that kids and young aspirants of tomorrow would love to read and learn from.