Indeed, Post-it notes are one of the simplest products out there.  They are literally just a square of colored paper with a strip of adhesive at the top.  That being said, the simplicity is the very feature that enables Post-its’ versatility.  Their function alone allows you to mark off pages in books–and the variety of color options allows for thematic organization that was previously unthinkable. Without Post-its, people had to actually flip through each page of a book in order to see what they had considered important.  Not only are Post-its an analytical time-saver, however, they are also incredibly useful in other contexts as well.  My personal favorite usage of Post-its is as a reminder mechanism.  Their unimposing size, combined with their noticeable vibrancy allow for unobtrusive, yet reliably recognizable calls to action.  That is why, when I really need to remember something, I will leave a Post-it on my door so I physically cannot forget.  These are just two of the many features of Post-it notes.  Their continued success speak volumes about how even the simplest of inventions can have such a wide range of continued usages.