Negative Information - how can we even know that it exists?

From Good Morning Silicon Valley:
Many of you will swear you've already seen this phenomenon in your own lives, but apparently it can occur only on the quantum level ("quantum" being Latin for "everything you know is wrong ... and/or right ... or not"). The phenomenon is "negative information," and researcher Jonathan Oppenheim does a yeoman's job trying to explain it in terms you can almost wrap your mind around (a familiarity with "Wheel of Fortune" helps): "What could negative information possibly mean? In short, after I send you negative information, you will know less. Such strange situations can occur because what it means to know something is very different in the quantum world. In the quantum world, we can know too much, and it is in these situations where one finds negative information. Negative information turns out to be precisely the right amount to cancel the fact that we know too much."