In reply to:

What on earth is a pocket protector?

a plastic pocket which fits inside your shirt pocket for the purpose of holding all your various colored ink-pens and pencils whilst protecting the fabric of said shirt -- standard issue to engineers and computer nerds during the 70s and on.

here's a particularly typical one:
http://www.powerup.com.au/~squadron/order.htm

the part with the logo is a flap which, when 'flapped' over your pocket and with pens clipped to it, holds the whole dingus in place.