That's because you render your GUIText off-screen.
Position (x,y,z) of GUIText Object is relative to screen ration. It must be within 0..1 range. 0,0,0 means bottom left of the screen. 1,1,0 is top right.
Also, you have coordinates 0,0,0 (lower right) and anchor "upper left". This renders your GUIText just below the screen. What probably want to archive is: Position 0,0,0 and anchor "lower left"
But you shouldn't use the legacy GUI anymore. With Unity 4.6 the new uGUI System is available, more powerful and more performant.
The old GUI system is just slow, each GUI element causes a draw call and this kills performance on every mobile device. And it's very hard to work with, if the UI gets more complex than 2 buttons