You can play with it, create new CRC cards, delete old ones, etc. The Good Thing is that if you locally save the page (with your browser
File -> Save Page As...), the saved file will contain your modifications. You can then point to your local file to update it again. You can also create a new whiteboard by saving it under a different file name..
It was quite a surprise to me. Initially, I thought that the
save function of the browser would save the static content of the page while what is saved is actually the DOM of the page even if some parts of the DOM have been generated dynamically.
I'll never stop to be amazed by the power of web browser!