From Showit Manual
You can work on the site from multiple computers. Keep in mind that Showit is a hybrid of a web and desktop application so your site is saved to your local hard drive and to the Showit server. When switching computers, the second computer may take time downloading files that were created or uploaded from the first computer. Be sure that you are online when saving (the green icon in the bottom right) so that changes are saved to the server and can be loaded on the second computer.
Best Practice: It is best to Save and logout (Account>>Logout) before going to your second computer. Then login to your account and it will load the most recently saved online. Be sure to logout if you will be going to the other computer so that you don't run into saving issues.
Showit defaults to loading the last saved version of your site saved on that computer. If you saved the site on another computer and you are online when starting Showit, it will warn you that a newer version has been saved online. Be sure to open this version if you want to keep the changes that were saved from the last computer.
If you need info on how to create multiple websites at different domain names, you will need to create Multiple Sites.
Sometimes when opening a site from another computer, the files in the media library are not in sync. This is because each computer maintains a local database of the assets for speed in searching and use offline along with the ability to queue assets for upload. These DBs should stay in sync but there is currently a bug we are working on to fix this.
If you open the site and the media library is not in sync, you can now click the refresh icon in the Media Library window to force the local database to sync with the database online.