Changes to information regimes do have profound effects. Their consequences are quite difficult to predict, and not necessarily good or evil, though that depends on deeper issues as well.

The emergence of the printing press and spread of knowledge, both official doctrine (the Bible), literature (Cervantes' Don Quixote was the first modern novel), ideas (Montaigne's Essays), scientific thoughts (Copernicus and Gallileo), and many, many pamphlets, shocked Europe for the next several hundred years. Keep in mind that a copy of Gutenberg's Bible, new, was the equivalent of about $4,500 based on one recent estimate I've seen -- expensive by modern standards, but previous, hand-written copies of books were the equivalent of handcrafted meticulous art-pieces. A scribe might be able to complete one or two books per year, and had to be fed, housed, clothed, etc., for this, as well as educated. Producing the vellum, inks, quills, etc., used, and candles (for any work beyond daylight hours) also has to be factored in. See: http://history.stackexchange.com/questions/21161/how-long-di...

With the dawning of the industrial age in the early 1800s, mass literacy became a thing. In England, literacy rose from ~40% to near 90% over the course of the 19th century, through publicly-subsidised education, required for the new, highly-skilled factory jobs. Paper became cheap, and presses faster (a few thousand sheets per hour), enabling yet more dissemination of information. Among the consequences, mass movements of the public, independent of demagogues, pressing claims, including the Chartalist movement in the 1820s - 1830s in England, and the Year of Revolutions, 1848, throughout Europe and Central and South America, in which 50 nations saw substantial rebellions.

The early 20th century saw loudhailers, which enabled the voice of one person to reach the assembled ears of tens or hundreds of thousands of people at once. Transport (busses and trains) could assemble them. Radio allowed a single voice to reach, instantly, an entire nation at one time. And declining printing costs allowed single books or manifestos to be distributed en masss (Mein Kampf, Mao's Little Red Book, The Road to Serfdom, etc.), often subsidised by a propagandist. The rise of fascism in Italy and Germany, and World War II, were a partial result, as was the spread of Maoist-Leninist Communism throughout China -- a difficult region to unify otherwise.

Television and mass advertising gave rise to live televised debates and speeches. Kennedy beat out Nixon in 1960 in large part due to the former's far better visual appeal on black-and-white television. Castro could keep all of Cuba tuned in to hours-long diatribes. Vietnam was litigated as much on American (now colour) televisions as in the jungles and rice paddies of south-east Asia. American technical competence was proved in real time via the Apollo Moon landings, and impeached by the Challenger explosion.

The corporatisation and commercialisation of media beginning in the late 1970s, but accellerating in the 1980s and 1990s, cheapened the product, silenced dissenters (particularly Noam Chomsky, though many others -- who've had little if any voice on either commercial or noncommercial television or radio), and enabled first right-wing talk radio, in part an outgrowth of what had long been a rural Christian revivalist movement in the US, then CNN's live, 24/7 cable news, and Fox.

The Internet gave voice to the voiceless, but more voice to the already empowered. Most particularly those who could act with impunity. Distortion, especially of political and economic discussion, from monied interests, Russia, China, Israel, and numerous fringe, crank, and terrorist groups, is manifest -- these are organisations which don't and won't play by the usual rules. Eyeballs-driven, advertising-supported Interent sites only feed this dynamic, one of the more substantive criticisms of an ad-based Internet I think can be made.

Francis Bacon gave us the phrase "knowledge is power" (actually "scientia potentia est"). With due respect, I believe the gentleman wrong: knowledge is a power multiplier. It amplifies the existing power differentials amongst parties.

It's also true that the ruling elite and popular movements have differing constitutions, capabilities, and weakensses. The former have organisation, capability, assets, and control, but suffer from vulnerability. The latter have resilience and adaptability, but little by way of organisation or even common interest. It's interesting to note that the idea of a popular revolution is a quite modern concept, dating largely to the 19th century. Previously, regime change was far more a matter of one oligarchy displacing another, though manipulations of mass sentiments might play a role.

For references: Edward Bernays (and Adam Curtis's The Century of the Self), Plato, William Ophuls, Marshall McLuhan, Jerry Mander, John Kenneth Galbraith, Joseph Nye, Neil Postman, Noam Chomsky, and of course, many others.