Disable iCloud message for new users on first login for OS X Mavericks

Launch Terminal and enter the following:

defaults write /System/Library/User\ Template/Non_localized/Library/Preferences/com.apple.SetupAssistant DidSeeCloudSetup -bool TRUE

defaults write /System/Library/User\ Template/Non_localized/Library/Preferences/com.apple.SetupAssistant LastSeenCloudProductVersion -string 10.9