On Tuesday, as the number of advertisers boycotting Facebook surpassed more than 400 brands, founder and CEO Mark Zuckerberg finally agreed to meet with civil rights leaders organizing the “Stop Hate for Profit” movement. The company is no stranger to such boycotts, with one in 2013 over gender-based hate speech yielding meaningful changes to its policies, while a 2018 effort over data privacy fizzled out. A closer look at all three boycotts shows the challenges ahead.