Have you ever increased the font size of a key point in something you wanted someone to learn? Maybe bolded a word or two to provide the proper emphasis? Maybe next time you should consider putting these important points in a small font or some unusual font if you really want them to remember.
One of my colleagues sent me this article from the NY Times basically stating that if you have to work harder or concentrate more on the words or passage you are more likely to retain the information. I can't count the number of times I've underlined, bolded, or otherwise provided some form of emphasis to a piece of text in the hope someone will retain it. At the end of the day the amount of effort we put in will normally equate to the result.