I have always wondered, where companies like Facebook, Google, or Snapshot register their domain name, at least when they first started, knowing that most of them have several web hosting services now.
The registrar that I have seen more of the big companies use is MarkMonitor. They have several services for brand protection and other things that the big companies like so many of the top companies use them. They really are not a traditional registrar for the most part but more of a specialty type of service.
The other one that I have seen many use is Network Solutions and that's is part because they were the first registrar that was used by most people long ago when domains were first being registered by companies and people.
A domain name registrar is an organization or commercial entity that manages the reservation of internet domain names. A domain name registrar must be accredited by a generic top-level domain (gTLD) registry and/or a country code top-level domain (ccTLD) registry. The management is done in accordance with the guidelines of the designated domain name registries (wikipedia).
Big companies that you have mentioned are using MarkMonitor. They are a specializing type of a registrar so big companies choose to use them. Typically they register their domain with their company name.
Always new Big companies like Network solution for register and manage their domains. Since the middle 90's Network Solutions has been in the market.
Actually i remember to buy domains in NS and use jaguar PC as hosting company. Few years later we also used Pear.com. well, but that was the time Tucows was still a big thing and i still had lots of hair ...
I agree that Mark Monitor the registrar many of the companies you mentioned patronize for registration services. This is due primarily to their expertise in intellectual property and copyright legislation.
Oddly, Google is a domain registrar, but does not provide registration of their own domain name...I find this to be an interesting (thought-provoking) tidbit regarding Google's emergence as a Domain registrar.