Check out the first couple bullet points on the "About the API" page:
> Simple HTTP+JSON method of accessing a user's information in a user approved sandbox on the user's desktop. List, upload, delete, move, copy, and get files as well as many other features... A full event callback API allowing you to get simple asynchronous events to your web site or service whenever the user changes their sandbox.
> Simple HTTP+JSON method of accessing a user's information in a user approved sandbox on the user's desktop. List, upload, delete, move, copy, and get files as well as many other features... A full event callback API allowing you to get simple asynchronous events to your web site or service whenever the user changes their sandbox.