Short answers, pulled from the story.
The Online Etymology Dictionary records "activist" in its political sense from 1915 and "activism" from 1920. As late as 1969 the word meant simply "the policy or practice of doing things with decision and energy," without any political connotation. The surge of new social movements in the United States during the 1960s transformed it into a recognized democratic form of protest.
Charles Tilly's "repertoire of contention" describes the full range of tactics proven effective by past activists, including boycotts, petitions, marches, and sit-ins, which any new movement can draw upon. New tactics can enter the repertoire through a social process called diffusion after they prove successful.
Beginning in late 2010, people across Middle Eastern and North African countries used social networking to share information about protests, including smartphone videos, bypassing state-controlled media to reach an international audience. It was one of the first occasions in which citizen-activists used social networking to communicate directly with the rest of the world.
Research shows that nonviolent tactics generally draw more public sympathy than violent ones and are more than twice as effective at achieving stated goals.
In 1930, thousands of Indians followed Mahatma Gandhi on the Salt March to protest the oppressive taxes of the colonial government. The campaign resulted in the imprisonment of 60,000 people and eventually contributed to India's independence.
Craftivism is a form of visual activism that uses creative work to send short, clear political or social messages. Those who practice it are called craftivists.