Livedrive gives each file a hash (randomly generated number) which is essentially its own fingerprint.

When you select a file or folder to backup the software searches for files which have the same fingerprint or hash, and if it already exists on Livedrive servers, it will copy the file instead of getting the LiveDrive software to upload the file again.

Even after you have deleted files and folders, they remain on the servers for 30 days, and after this time are permanently removed.

Using this technology (de-duplication) Livedrive prevents customers having to upload entire files and folders they may have previously uploaded to the servers