The extension of the popular vote in presidential elections changed political campaigns, making them truly mass events with huge levels of participation.
Before the extension of the franchise, presidential elections were more staid affairs. There was not generally a great deal of campaigning. This changed by the mid-1800s. The election of 1840 is generally seen as a major turning point in this process. This was an election in which there were massive campaign rallies that created a sort of carnival atmosphere. The Whigs' campaign rallies featured the distribution of hard cider (alcoholic beverage) as a way of dramatizing the supposed difference between their candidate, William Henry Harrison, and the Democrat Martin Van Buren. The idea was that Harrison was a backwoods type who drank hard cider and lived in a log cabin while Van Buren was an elitist Easterner.
As the popular vote was extended, campaigns underwent a major change and came to look much more like the campaign of 1840.