For most of human history, people had only their own memories for storing information. Most people who have lived did not know how to read or write, and if they wanted to remember something, they had to memorize it. Stories and poetry helped people to remember things.
With the advent of mass printing, and then typewriters, duplicators and photocopying machines, the printed word came into its own. Memory could be put to paper; the memories could be profound — the Iliad, the Bible, Shakespeare — or trivial: an order for a hamburger and fries.
One of the great advances of the latter part of the 20th Century was the mechanization, then automation, of memory. Originally, computers were designed to compute: they were custom-made for things that could be added, subtracted, multiplied and divided things. Today, by far the largest and most important use of computers is for memory: storing photos, songs, movies, bank records, electronic books, and anything else that can be described with ones and zeros.
Alas, automated memory is not perfect, as seen in this photo. A shopping mall placed a computer in the ceiling over a hallway in a shopping mall, with a projector pointing down onto the floor, advertising something. Exactly what was being advertised is not clear; the poor Windows XP computer had a memory management problem, and projected its problems onto the floor instead of the advertising.