Public Journal is a way to share your notes or book reviews with the world. After you enable it you will get a special URL which you can send to your friends. Note that by default it is turned off. In order to switch it on go to Settings > Journal and switch it on. Then you need to choose a "slug" and type it into the box. After that your journal will be available. For example, here is mine.
It's easy. Right under the dropdown there is a little date shown. This is the date when you have finished that book. Click on it and a little calendar will show up where you can pick a different date.
Mobile apps are available on Google And Apple Stores. Click one of the links bellow.
Go To Settings > EXPORTS. This operation can take some time. So refresh the page in several minutes, and then you should be able to download all your data.
Go To Settings > DELETE. Please note, this actions can not be undone. Your account will be removed immidiately and there is no way to restore it.