Protesters are using a variety of technology tools to organize rallies, record police violence and communicate during the marches sweeping the U.S. and other countries following the death of George Floyd. Some of that involves secure messaging services like Signal, which can encrypt messages to thwart spies. Those apps, along with others for listening to police scanners and recording video, are enjoying an uptick in popularity. But experts say convenience and reach remain key, which favors standbys like Facebook, Instagram and Twitter. White nationalists, however, are also turning to apps like Telegram to blast disruptive messages to their supporters, hoping to wreak havoc on demonstrations.When a friend shared a Facebook post with Michelle Burris inviting her to protest in downtown Washington, D.C., last Saturday, she knew she had to go.…