When you setup your Google Custom Domain , you enjoy the personal satisfaction of having your own non BlogSpot URL. You publish your blog to a non-Blog*Spot URL on a Google server, and your BlogSpot addresses still works. This setup lets people and processes like search engine spiders continue to find your blog in BlogSpot, while you enjoy your non BlogSpot URL. You define your domain, and how the content is hosted, using a series of "A" and "CNAME" referrals, pointing to Google . Before you can do that, your registrar has to define how the domain is hosted, using a series of "NS", SOA, and related records . The latter task lets your registrar maintain your domain, and hundreds of others - with each domain sharing their servers, reliably.
What Blogger won't tell you