I think this is useful as it provides an easy way to test a site before any DNS records are pointed or if you want to visit a domain that doesn't have public DNS. being able to visit the site through your browser is alot easier than other solutions I have found such as editing your hosts file on your local PC.
I would appreciate it if you could check it out and let me know if you find any errors / problems. Let me know if you would find it useful / helpful as well
The domain name is: http://propagationproxy.com