Sanjoy Mahajan at freakonomics.com has an interesting piece on Colonial literacy, looking at the success of Tom Paine's 1776 "Common Sense" which in one year was read, or at the very least bought, by 20% of the American colonial population. Translated into today's US population, that is the equivalent of of a book selling 60 million copies. Few books attain that level. It took 8 years for The Davinci Code (a book not about common sense) to reach that level.
Although the words are short, the language and reasoning of Common Sense is rich and complex. Here is a very small example:
Society in every state is a blessing, but government even in its best state is but a necessary evil; in its worst state an intolerable one; for when we suffer, or are exposed to the same miseries By a Government, which we might expect in a country Without Government, our calamity is heightened by reflecting that we furnish the means by which we suffer.
You may be a different case, but I did a double-take or two, to make sure I was carrying the sense well enough to go on the the concluding punch line. Such complexity is at the heart of reading for meaning. The current National Assessment of Adult Literacy classifies the above text as being at the highest level, Proficient Reading, only attained nowadays by 13% of the American population.
So, despite the apparent rise in intelligence suggested by the Flynn Effect, proficient reading has fallen from an implied 20% to a measured 13%, using comparable measures of complexity.
Mind you, 1776 was something of a special year for Americans, one which encouraged serious reading. They may have made a particular effort to understand the text. Either that or they read proficiently, inwardly digested, and came to their own proficient conclusions. Paine's view was clear: "To have had a part in two revolutions is to have lived to some purpose."
Regard him as one of the early bloggers.