Whats the technology behind sites like (Google Sites, Shoppify etc)?

Question

I am wondering how sites like Google sites and shopify allow customers to create a website and then link it to their own domain?. Google sites allow a user to create their own website, at a user supplied domain, and shopify allows a user to create their own e-commerce site - once again, they can supply their own domain to be used to access the webshop created.

In both cases, the website is ostensibly accesed by typing the users domain name in the browser, although the website is actually being hosted by a third party company (Google, Shopify etc)

How is this possible?. Does anyone have an insight into how this is (likely) being done?

Answer 1

Subdomain RewriteRule

why dont you use mod_rewrite rules to do the trick http://forums.digitalpoint.com/showthread.php?t=33868

Answer 2

I imagine that the technology is DNS, or more precisely CNAME records which alias one DNS name (e.g. "vole-strangling.com") to another (e.g. "vole-strangling.sites.google.com").