The current mechanisms for pointing domains to StackExchange sites (using either CNAME or A records) are fine for users that are comfortable messing around with their DNS settings, but for users with nothing but SE on a specific domain it would be simpler if they could just point it at FogCreek/StackExchange nameservers and have the SE service take care of managing IPs and records.
Not only would this allow FogCreek to change the IP of the service (or provide multiple IPs for failover) without forcing the user to use a subdomain (like www), this would also be useful if the StackExchange service would provide multiple sites on a single account/domain. In addition to providing the main SE site, I imagine many users would want to set up a testing site to test changes to the design/advertising, and a Meta site to provide support for the community, but manually managing the DNS for multiple sites can get tedious after a while.
