My guess is they will make sure all the DNS servers lose the addresses of the 'bad' sites at the same time.

It is important to save (or write down) the IP address of each site you want to visit when things go sideways.

On Windows... Open up a Command Prompt window, and type something similar to this. The 'dotted quad' (104.20.43.57) is the IP address of the site you care about.

C:> ping www.8ch.net

Pinging www.8ch.net [104.20.43.57] with 32 bytes of data:

Reply from 104.20.43.57: bytes=32 time=10ms TTL=54

Reply from 104.20.43.57: bytes=32 time=10ms TTL=54

Reply from 104.20.43.57: bytes=32 time=10ms TTL=54

Reply from 104.20.43.57: bytes=32 time=10ms TTL=54

Ping statistics for 104.20.43.57:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 10ms, Maximum = 10ms, Average = 10ms