This service seems to be necessary for the control panel. If it is not running the control panel fails to open, and the start menu submenu is empty. I didn't notice any other major symptoms from setting it to manual, but I didn't really look.
Actually, the SL UI Notification Service is responsible for the control panel failing to open... and it requires Software Licensing to function properly. As such, if you disable Software Licensing, SL UI Notification Service will not work, which then breaks the control panel.http://www.blackviper.com/WinVista/Services/SL_UI_Notification_Service.htm