I'm looking for some guidance on my research to building an SaaS. This thread seems to be related, but I'm wondering if this software Rackspace has called rBuilder is what I would be looking for to automate the process of creating an instance of the software with a unique IP address and domain name.
Also, for an application similar to Shopify, does the application work like Facebook where it serves up different information based on the account, or is it better to have separate installs of the software like WordPress, but on a server that you maintain?