smoke and mirrors

smoke and mirrors n.  Marketing deceptions.  The term is
   mainstream in this general sense.  Among hackers it's strongly
   associated with bogus demos and crocked {benchmark}s (see also
   {MIPS}, {machoflops}).  "They claim their new box cranks 50
   MIPS for under $5000, but didn't specify the instruction mix ---
   sounds like smoke and mirrors to me."  The phrase, popularized by
   newspaper columnist Jimmy Breslin c.1975, has been said to
   derive from carnie slang for magic acts and `freak show' displays
   that depend on `trompe l'oeil' effects, but also calls to mind
   the fierce Aztec god Tezcatlipoca (lit. "Smoking Mirror") for
   whom the hearts of huge numbers of human sacrificial victims were
   regularly cut out.  Upon hearing about a rigged demo or yet another
   round of fantasy-based marketing promises, hackers often feel
   analogously disheartened.