When printing something off of the internet, there is a bunch of junk on both sides that is a waste of ink and space, including advertisements (like on Facebook), when you just want to print a simple coupon from a website, sometimes you end up printing all kinds of things that are totally unnecessary. In Windows there is a way to adjust margins on your page, a way to stretch out the sides so that they are left blank, without all the extra stuff. Left margin and Right margin options. Kind of like the Header and Footer, only on the sides of the paper.