I love using index cards for notes and memos. The other day I started to wonder how big they were in terms of MB. I can write about 10-11 characters per inch, so we’ll say 10 characters, conservatively. A college-ruled 3x5 inch index card has 10 lines. So, 10 characters per inch, for 5 inches per line, for 10 lines, gives us 500 characters per side. If you count a “title” of 24 characters, that gives you a roomy, conservative 1024 ASCII characters, or a 1 kilobyte of data, if you write on both sides.