There is nothing new under the sun. People say, "look, here's something new", but it already happened long ago.
Honestly, I don't think the situation is all that different from the situation throughout human history, except that a small group, or even an individual, can have major impact now. Try making an anonymous bomb threat*, say about a train station, and you can cause a lot of disruption. If you want to get into the media, just tweet a death threat* at somone notable; it doesn't matter that you have no way of carrying out the threat, you'll be held up as an example of Internet Troll Harrasment and used to explain why everyone the individual disagrees with is a Terrible Person.
That's not even talking about doing something concrete. Next step up, start a YouTube video and blog in which you rant about how X are Destroying Civilisation.`Make it as over the top as possible, and you can reach millions of people in a very short time. Sure, most will be watching you to have a laugh, but some will listen. People like certainty in their talking heads, more than they like humility.
If you're really willing to get murderous, blow something up*. Or get a drone to, so you don't have to risk your life. Maybe make a Killer Drone Of Death, with spinning blades, and fly it through a crowd*. If you want to get genodical, it's time to break out the biology textbooks. You'll want to build a suitably deadly pathogen*, but probably with a vaccine as well so you and yours can Survive The End Of The World. Again, drones are great, you can use them to spread this over large crowds of people. Give it a few weeks, and society will collapse under the strain, though it might take a few months before you and The Chosen can emerge and conquer the ruins.
They should really pay me to come up with these scenarios, and work on countermeasures...
*Actually, don't.