It's not a concern...see the answer above regarding the web cam light. My question is......why do people think someone has control of their Mac web cam? Is this concern based on any real, active threats?
My hunch is that the (very real) threat of a remote controlling a Win box (well before Win 7) and thus taking control of everything (including a camera) was a legit fear for those users....who then ran around yelling the sky is falling......not knowing or caring that it is/was in fact an OS specific threat. They tell everyone they know....and 5 years later, we see Mac users putting tape over their camera.
So my question stands: Why are Mac users nervous? Is there any evidence of a real threat to patched, up-to-date Mac?