[vocatus_gate]

I always thought it was "Fake User Interface."

[ThinkingGuy]

Yes, I always heard "FUI/Fake User Interface" used to describe those deceptive pop-up advertisements meant to look like a Windows system window (usually with some nonsense warning like "Your computer is broadcasting an IP address!").

[davidgrenier]

I simply stopped reading presuming it meant Futuristic User Interface.