[plainnoodles]

There is some level of importance in bigness. All the major public resolvers let nameserver operators (well, anyone, really) clear cached records. Which turns out to be a not-uncommon occurrence. I wrote my own DNS server, so I've been paying a ton of attention to this stuff, and I've found several scenarios where website operators (even, for instance, instagram!) seem to have wanted to change some DNS records but weren't happy with the TTLs they'd advertised on them, and instead of waiting them out, just cleared caches with the major resolvers and then gone ahead and turned off the old IPs.

With the end result that I had to go in and remove those records from my cache, too.