Any given "Sync Folder" enables you to synchronize one disk folder (with all its files and folders inside) with your own devices or with other SYNCING.NET users. Every change in the folder on any of the devices sharing the "Sync Folder" will be done also on all other devices (adding files, changing files, deleting files). However, when you delete files, they will be moved to Recycle Bin on every device. You can define the location for the shared folder on all computers sharing the "Sync Folder".
You can create multiple "Sync Folders". E.g. one "Sync Folder" to share a folder with all files for a specific project between all your colleagues and another "Sync Folder" to share your "My Documents" folder in Windows between your PC and laptop.
In other words, a "Sync Folder" describes which data (a given folder and all its files and subfolders) you want to share with which person or device.