Mind Blank was reportedly created by Dalis. Dalis had long been a first hand witness to the forgetfulness a pretty face can create on the members of the opposite gender though this effect is quite more predominant among men. Guilty as charged I'm afraid. After spending some time studying this effect sometimes rather enthusiastically she found that certain actions could enhance this forgetfulness. By combining these actions she could reproduce an effect much similar to the current version of Mind Blank we all know and use. Of course since most of these actions could not be repeated in public she had to find a different way. Dalis examined the very nature of our avatars and found that there is one portion of us, which is always active but when deactivated, does not cause any noticeable effect, save one. Naturally, as I'm sure you can guess, it prevents Location. There's been a fair amount of speculation about how exactly the Art works or where this portion of our avatar is... But not much holds water. So we are left with an Art that we know vaguely how it works but not it's deepest secrets. There are about three major schools of thought on it, though one is ridiculous and held only by the very newly awakened. The first school as I mentioned, states that the art "turns off" a portion of our Avatar namely the one that allows us to be located. The second states that Mind Blank erects a sort of protective shield around us that blocks the emanations from this particular portion of us. The last school, and keep in mind this is quite silly really, thinks that there is some sort of "flag" set by Mind Blank and when Locate Dreamer sends a "request" to some nonsensical Dream central... it will refuse to report their location. This disagrees with what we know of Locate Dreamer too, so it's widely rejected.