@Piotr, that was not a rant. This is a rant.
When you change IP addresses you know there will be DNS timeout issues. You know that things won't work for one, two, three hours, for random users. This is not mysterious, it is 100% predictable.
Yes, my sites were technically accessible. However I had complaints from users, and collaborators, who asked me why things were not working. I spent some time wondering if there was an SSL issue, caching issues, cookie issues… and then gave up and did other stuff. As far as my online business was concerned, Wikidot was down for a couple of hours.
Yes, it all started working again afterwards.
But there is no excuse for doing this kind of change during working hours. It's unprofessional and lazy. That is what 5am is for, so it all works by the time people wake up and start to use their Wikidot sites.
Now that's a rant. At your service, any time.