A perceptive point by Neil Postman:
"...[C]onsider the primitive technology of smoke signals. While I do not know exactly what content was once carried in the smoke signals of American Indians, I can safely guess that it did not include philosophical argument. Puffs of smoke are insufficiently complex to express ideas on the nature of existence, and even if they were not, a Cherokee philosopher would run short of either wood or blankets long before he reached his second axiom. You cannot use smoke to do philosophy. Its form excludes the content."
And similar limitations, I would add, exist on Twitter.