The Problem Isn't Twitter
The gaps in Bernie's online support and his showing at the polls have lead to a lot of condemnation of online activists. These have taken the form of "tut-tut" think pieces, and finger wagging Facebook memes condemning millennial for not voting enough.
The idea of online activism has been condemned since it first reached mainstream attention during the Iranian "green revolution" in 2009.
So for seven years we've had to hear how online activism isn't real activism, and that these actions are really just slacktivism. Worse yet these actions can feel people with a sense of accomplishment without having done anything, and prevent them for doing something "real."
Much like a well placed lawn sign or bumper sticker, online activism is obviously nothing more than a signifier of belief. What we don't have is a lasting record of the people who put out lawn signs that we can compare to voter turnout data.
The battle in politics has always been getting people out when it matters, something that isn't always easy. I'm not saying that Twitter and Facebook are important tools of democracy, but they are a channel of communication. If you doubt the power of the Internet, the leading Republican candidate has been running a stream of consciousness campaign on the service since before anyone bothered taking him seriously.
So Twitter and Facebook supporters are bullshit, but politics and protests are full of people who didn't show up when it counts. You can condemn millennials for failing to show up, but it isn't because of technology. It's because they're human.