This doesn't seem very... sane. It does work, but the explanation is wobbly at best. This appears to be a King Kong defense converted into a sales tactic. In

This doesn't seem very... sane. It does work, but the explanation is wobbly at best. This appears to be a King Kong defense converted into a sales tactic. In their theoretical problem, foo.com needs to be moved to somewhere else in a hurry to reduce an unpleasant load level. No problem--you simply change where foo.com points to. Normal people change the A record and call it a day. Why would you want to involve a CNAME in this? Perhaps if you needed to direct the query to some other server because it's managed by some other entity. But wait... This requires the other entity to serve your DNS records. Not exactly a problem--even though it rather uncomfortably resembles a horizontal referral--so long as we exercise restraint, it only slows down the query a little bit. So now the lookup goes to the server your domain (foo.com) is hosted on, and needs to goes to the other server to get the foo.com.fancynametheycanmove.webprovider.com, except no... that won't really work because your DNS provider hosting foo.com would need to allow you to put CNAMEs at the root of the zone, and CNAMEs are singleton records. The solution? Why it's to use webprovider.com to host your foo.com DNS as well! Then they can do this because their magic DNS server does all those other lookup steps for the querying client. But wait... if they're going to be hosting the foo.com zone, why don't they just change the A record in the first place? Why on /earth/ would it be useful to involve a bunch of CNAME jumps in that? For that matter, how is this even slightly usefully different than a normal global traffic manager issuing different responses for DNS based on load and server pool configuration that for the love of all that is holy I hope they already know about if they're trying to run a "cloud provider". The reason we don't have CNAMEs in the root of zones isn't "because the standards are old" it's because CNAMEs are supposed to be a one-off which should be used sparingly because they can be used to create never-ending chains of indirection which cause serious problems for nameservers doing recursive resolution for their users. AOL used to regularly break nameservers all over the place with their casual use of endless loops of CNAME records.