A user can also trivially defeat any password system by publishing their password to Facebook. The purpose of preventing similar passwords isn't to prevent a u

A user can also trivially defeat any password system by publishing their password to Facebook. The purpose of preventing similar passwords isn't to prevent a user from defeating themselves, it's to prevent an adversary from defeating the user. Now you can rightfully argue that blocking similar passwords isn't an effective measure against an adversary, and this article kind of suggests that... but it is possible to implement such a system.