Siteman has Live Update (LU) whereas all Binary Bit Templates, Modules and Components are LU capable — meaning that if you have Siteman you can use LU to update all our extensions.
Developers can take advantage of this feature and add LU capability to all their Joomla Extensions as well: See LU SDK
Live Update isn't a new concept, but in the Web Application world it isn't implemented all that often. Live Update allows the the user to check for updates with a click of a button, chose the updates they want, and with another click update their web application. With Live Update there is no longer any need to uninstall, reinstall, manually FTP files, or manually update databases.