Why is this important? If you have a custom domain, only the 'www' address will point to your Cindr site, a naked domain won't (unless you follow the advice given here).
Why won't a naked domain point at Cindr? We have multiple servers (all with different IP addresses) and any of them might be hosting your Cindr site at any one time. With most domain providers, setting up a naked domain to point at Cindr requires you to enter the server's IP address, but because we may be hosting your Cindr site on different servers, this means that your naked domain will often not be pointing at your Cindr site. Therefore people using the naked domain will get an error message rather than your site. This is why in our guide to setting up a custom domain, we advise you to set up a CNAME record but naked domains can't point at CNAME records.
How can I get my naked domain to display my Cindr site? Easy - there are various examples free 3rd party software that can point your naked domain at the www domain.
What software will do this? wwwizer would be our recommendation. As with any 3rd party service we advise you to do your own research to make sure you're happy with their reputation first.