Have the benefits of handwriting and the convenient of having all your index cards online.
An app that is made out of index cards you fill. The app recognizes your handwriting and converts it to text. You can choose to display your original hand written version or the converted text. You can also categorize each index card, view them on a virtual board in different magnifications, mix them, move them around, share them and print them.
Wouldn’t it be interesting if we could look at other people’s notes and what they highlighted while reading a certain book?
Allow people to add their own notes to listed books (and add new books if they are not yet listed), and keep them in a central repository online. Everything should be indexed and searchable.