In Europe printing was a strictly guarded procedure that involved getting permission from the government. Free speech did not exist like it does today. In America things were different. Prior to the 1850s the colonies were not united and each governed themselves to some extent, but Benjamin Franklin and other printers began to produce copiously and they made political statements that would have been illegal in Europe, like the cartoon above. This cartoon was then reproduced in all the colonies papers, and began the print culture that helped unite the colonies, ultimately resulting in Revolution.
The American Revolution is the ultimate underdog story, and as such Americans can't stop retelling it. We're proud of what our forefathers did: of the Boston Tea Party, Paul Revere, and beating those redcoats. In today's internet based society, print culture has changed once again. Now anyone can post anything they want on the internet (like my blog,) and instead of uniting 13 colonies it unites the world.