In case you were interested:

In 1888, Thomas W. Holley, a 24-year-old paper mill worker in Holyoke, had an idea for how to use the paper scraps, known as sortings, discarded by the mill. Sortings were anything trimmed away as scrap or considered of lesser quality than the writing paper eventually packaged and sold. Holley's notion was to bind the scraps into pads that could be sold at a cut rate. Convinced he had a winning idea, he founded his own company to collect the sortings from local mills (Holyoke was then the papermaking capital of the world) and began churning out bargain-price pads.

The legal pad's margins, also called down lines, are drawn 1.25 inches from the left edge of the page. (This is the only requirement for a pad to qualify as a legal pad, though the iconic version has yellow paper, blue lines, and a red gummed top.) Holley added the ruling that defined the legal pad in the early 1900s at the request of a local judge who was looking for space to comment on his own notes.

That, at least, is the story AMPAD tells. Holley never filed a patent for his invention; no other company in the legal pad market has ever come forward with a competing claim. Like many origin myths, AMPAD's answers some essential questions but leaves others unresolved. It doesn't, for instance, explain the emergence of yellow as the standard legal pad color. Holley is thought to have created white pads, not yellow ones. Yellow paper is about 10 to 20 percent more expensive than white paper, due to the cost of dye and the additional cleanup the dyeing process necessitates, an extravagance the thrifty Holley would likely have dismissed.

...via BoingBoing