Final answer:
Yellow journalism became popular in the US by using sensationalism and exaggerated stories to appeal to emotions and increase newspaper sales, exemplified by publishers Hearst and Pulitzer during the late 19th century.
Step-by-step explanation:
Yellow journalism became popular throughout the US because it appealed to readers' emotions with sensationalism, scandal, and exaggerated stories. This form of journalism emerged in the late 19th century amid competition between newspaper magnates like William Randolph Hearst and Joseph Pulitzer, who sought to boost sales and outdo each other with compelling and lurid tales, often at the expense of factual accuracy. Their approach used bold headlines and riveting pictures to captivate the public and sell more papers, fostering an environment where the lurid and the sensational overtook the importance of objective journalism.
Pulitzer's New York World and Hearst's New York Journal pioneered this style of journalism, turning major events into melodramatic stories that intrigued readers. This tactic was seen as a way to pay off the costs of expensive state-of-the-art printing presses.
War stories, in particular, were sensationalized to such a degree that they stirred public emotions and swayed opinions, as evidenced during the timespan leading up to the Spanish-American War. Over time, this form of journalism influenced public perception and significantly impacted the course of events, such as the aforementioned war and the push for imperialism.