I'm not an expert Cleo, but I'll give my understanding and people can correct me where I'm wrong. I figure I'll give this a shot and see how far off I am.
Your registrar registers your domain within the(.com,.net, etc.) and says "the nameservers for this domain are here(wherever you say they are). That info is stored in the ROOT servers as well (theres a bunch). If you are using the registrars DNS servers as your main DNS and they get knocked out, people may see some disruption. I'm guessing your DNS is served by your HOST and not the registrar so the registrar being offline would be nothing major, other than not being able to get new domains there for a while
. Even if your DNS goes offline, depending on what your DNS record expiration rate is, who's caching your DNS info, etc...you could still be accesible by people who have your info stored. Just like a new domain takes time to propagate, it takes a little bit to die off, but it sure does die quicker than it goes active hehe. Thats my understanding of it, as a layman.
just think of it as a big pyramid scheme.
ROOT
SERVER1 SERVER2
SERVER A1 SERVER A2 SERVER A3
YOUR NAMESERVER1 YOURNAMESERVER2
Like a mailman finding the house(host101).street(domain).town(com) each portion of the DNS network knows where to point people bassed on what town, what street, and eventually someone knows which house you are in.
EDIT: CD Beat me to it
