Final answer:
Social media's influence on mainstream media can be seen in examples like CNN's "iReport" and social movements like #MeToo and #BlackLivesMatter, which began or amplified their reach through social media.
Step-by-step explanation:
An example of social media influencing mainstream media content can be seen in the integration of citizen journalism into traditional news sources. One specific instance is CNN's "iReport", which invites the public to contribute to news reporting. Additionally, social movements like MeToo and Black Lives Matter that started or gained significant traction through social media hashtag campaigns are examples of social media's impact on broader societal discussions and subsequently, the coverage by mainstream media.