Actually Google makes it pretty clear that they aren't a domain registrar, and their sign-up process used to encourage you to get a domain before you get starte

Actually Google makes it pretty clear that they aren't a domain registrar, and their sign-up process used to encourage you to get a domain before you get started. I am curious as to why they don't serve as domain registrar. I actually have my Google Apps domain through Yahoo, who used to host my mail....