Pixel Shift moves the entire screen by one or more pixels (depending on the settings), and it's a screen burn protection set - by default - to on. You could turn it off, however I recommend leaving it turned on at all times. Most people don't notice that it's on, even in the highest settings, but it is working to avoid image retention.
I just received my PN50B860 and would like to know about the pixel shift function. Is best to leave it turned on or run intermittedly?