This messaging is related to some of the backend changes going on that I mentioned yesterday. The change is that we do indeed have a new account management system. Due to some showstopping last minute issues the implementation of this new system was delayed by a day, subsequently delaying the server maintenance, which we announced yesterday. Unfortunately due to many processes running simultaneously, some of the information was made public earlier than the rest.
We will have more information and details about the NC Account (yes, based on email address) tomorrow. As mentioned previously, rest assured that this change will not forcefully impact players. Migration to the new account system is optional for months, and even when it is required in the future it will not force anyone to lose accounts or characters in any way. I know many of you will have questions, and you are free to read the linked FAQ for answers, but beyond this please remain patient until the full announcements are made tomorrow.