"One of the peculiar traits [of the public] is the insatiable appetite which exists in all classes of people in this country for news. It is thirst so universal that it has given rise to a general and habitual form of salutation on the meeting of friends and strangers of 'What's the news?'"
(Nathan Hale, publisher of the Boston Daily Advertiser, 1817)
Four men in front of a tent which advertises the Boston Daily Advertiser courtesy
Before the advent of the radio and the television and the computer, the newspaper was the public's main source for news. Newspapers first appeared in the Thirteen Colonies in the 1700's. However, America's population was small and it hadn't yet broken off from Britain.
Reporters on the Eastern seaboard used to wait for ships to arrive from Britain, row out to meet them, climb aboard and record the latest news. Then they would typeset back at the office, print it on the printing press, and share it with the locals. The process was slow and tedious and expensive. Only a small number of Americans subscribed to newspapers for a hefty sum.
The telegraph was the first device to separate transport and communication courtesy http://ushistoryimages.com/images/morse-telegraph/fullsize/morse-telegraph-4.jpg.
Three inventions changed the course of the newspaper: the printing press, the telegraph and the railroad, all of which made the dissemination of news much faster and more efficient. In the early 1800's, the United States only had 376 newspapers in distribution. However, by 1835, that number had shot up to 1200.
In his book Fanatics and Fire Eaters: Newspapers and the Coming of the Civil War (http://www.amazon.com/Fanatics-Fire-eaters-Newspapers-History-Communication/dp/B005IUWPDW) Lorman Ratner calls the sudden increase in readership a "newspaper revolution" and compares it to the transportation revolution. With printing presses becoming faster, and the population exploding, newspapers became cheaper and more readily available.
The Liberator masthead courtesy
Newspaper editors and reporters influenced public opinion by the images they evoked. Abolition was one major issue that used the newspaper as its forum, driving up its sales. The Boston paper, the Liberator, advocated the abolition of slavery. With an ever-increasing circulation, the paper helped open the eyes of the public to the evils of slavery. In its first issue, the editor appealed to the public, reminding them of the famous line in the Declaration of Independence that:
"'...all men are created equal, and endowed by their Creator, with certain inalienable rights -- among which are life, liberty and the pursuit of happiness.' I shall strenuously contend for the enfranchisement of our slave population."
When the Civil War broke out, it was the newspaper reporters who reported from the battle front. It was the newspapers that reported on the issue of emancipation which divided the country. The public's thirst for news was insatiable. They wanted blow by blow accounts of the battles. They wanted to know who was winning the war.
Whereas in Andrew Jackson's years in the White House, only a small elite read the newspaper, by the time Abraham Lincoln took office, the lower classes were reading the paper as well. In the end, the slavery issue was fought on the battlefield, and resolved with the ratification of the Thirteenth Amendment, thanks in part to the eye-opening headlines of the early abolitionists.