rscott13 - 8:45 pm on Sep 1, 2011 (gmt 0)
I'll try. :)
In the case of the search engine that is blocked by GoDaddy's new policy, the search engine will try connecting to millions of websites. When it tries going to most websites, it looks up the IP address of the website using DNS, and it goes to the website, gets webpages, stores them, indexes them, etc.
But, if you have a domain that uses GoDaddy's DNS hosting (which is the case if you registered a domain through them, and didn't tell GoDaddy to use different DNS servers), the only way someone can find out the IP address of your webserver is to connect to the GoDaddy DNS servers. So in this case, the search engine won't be able to find out the IP address of your server. The search engine can try sending the DNS queries to the GoDaddy DNS servers, but GoDaddy blocks them, so the search engine never gets the IP address of your website. So it cannot go to your site, get webpages, store them, etc.
It is not clear at this point exactly who this new policy affects. Certainly search engines like Google and Bing are not being blocked, but some/many lesser known projects are.