After the site is done or has at least some content, you can publish it (you will be able to continue editing in the future). Publishing is a process of copying the site's files from the SiteBuilder's temporary storage to the special place belonging to your user account called FTP server directory for permanent storage. Only regular users can publish their web sites - guest users do not have such possibility. However, what you do in the guest mode is not lost forever after you finish editing. You have a possibility to transfer your data made in the guest mode to an account of a regular user, e.g. when you will have one.
So, there are two cases of publishing the web site: