The purpose of stating the characteristics is to make sure we use the best match between the information and the visualizer. For instance, it's not a good idea to use note size to show status since the status is changing very often and note size is hard to change. If you have hundreds of customers we wouldn't recommend that you use rows to visualize them. Text is probably a better choice. On the other hand, if you have just a handful of customers, using rows to visualize which customer the work comes from is great. If you´re interested to see which customer is giving you the most work the color of the note is great since it's very visual when you have a board full of notes.