Emma Gonzalez, a senior at Majory Stoneman Douglas High School — where 17 people were shot and killed two weeks ago — is quickly gaining visibility as a gun violence prevention activist. And on Saturday, the teen’s already powerful impact became even more apparent as she surpassed the NRA in Twitter followers. The 18-year-old rose to prominence after giving an 11-minute speech at an anti-gun rally in Fort Lauderdale two days after the mass shooting, and for standing up to NRA spokeswoman Dana Loesch at a town hall hosted by CNN. This weekend, Twitter users noticed that Gonzalez had more...