Bob Bailey traces the spread of the popular “7 plus or minus 2” meme: “I have had people tell that [Miller’s] ‘Magic 7’ paper is the reason why the local telephone number has seven numbers. This is not true. I have had others tell me that the ‘Magic 7’ paper is the reason they:

• place only seven items on the menu bar,
• place only seven items in a pull-down menu,
• have only seven bulleted items in a list,
• never have more than seven radio buttons or check boxes together, and
• place only seven tabs at the top of a website page.”

—Reducing Reliance on Superstition (Let’s Start with Miller’s “Magic 7”)Human Factors International)

Found via Ron’s Ramblings.