You don't really give us very much info either......like what age is your son?
Maybe he ain't looking at porn at all - maybe he is just chattin with his friends and doesn't want you to see? Much the same as he wouldn't want you listening in on his phone calls!!

If you entered the room and started reading his chat convo of the screen it is basically the same thing!! Would you like people reading your private msgs? Or spying on you?? No I didn't think so - so why are you going to do it to your son?

Instead of being so sneaky why don't you just ask him about it? Don't seem angry or annoyed just concerned and you may find that its not as big a deal as your making out!!

v_Ln