“That way, if an account gets exploited, the creator himself can, at any time, close the account and prevent any damages.”
This sounds a lot like Wikipedia’s “user committed identity” system: you can set-up an SHA hash for your profile to be able to prove you are the legitimate owner of the account in case of a compromised account: http://en.wikipedia.org/wiki/Template:User_committed_identity
In all fairness though, if you are going to be using this as your personal blog you probably want a slightly higher level of security than can be offered by NNF’s current simplicity. Some more up-to-date security practices (salted scrypt, or at least bcrypt, hashes for passwords) would be a start.
Or maybe go password less? Several people have been trying this in the last couple of months. One-time-passwords sent to an app or email address, or just an instant login link in an email message. This would be pretty simplistic for users, but is non-trivial to implement.