Multiple domains can point to one TYPO3 site within the same database and installation. So several sites could be supported from one TYPO3 back-end! Imagine you have two sites with different content in different domains. You do not have to install TYPO3 twice. You can manage both sites from one back-end. Of course, two is not the limit - you can have as many domains as you wish connected to one TYPO3 installation.
