As anyone who makes it out of high school alive knows very well, the cafeteria is not a psychically, emotionally, or intellectually healthy place to be. And neither is Twitter.
Twitter is a place where the desire for approval can motivate people who work in politics and the media to mold themselves into what they think their peers and their audience want them to be, which often means more of what they already are. So a conservative will tend to become more conservative. Same with Trump supporters, with those on the left, and those, like me, who mainly reside in the liberal center. Over time just about everyone ends up becoming further entrenched in their own positions, with persuasion a virtual impossibility.
Twitter is a place where the means of communication vastly intensifies the always-powerful drive for speed in the news business. All news outlets want scoops. Normally a story can’t be counted as a scoop until it’s been published by a news organization. That can’t happen until the story has been verified, checked, confirmed, and edited. But now reporters and other journalists have an incentive and a means of enjoying the professional accolades that accrue to a scoop by tweeting out unverified rumors or retweeting someone else’s unconfirmed assertions. And that helps both to spread conspiracies and to advance the nihilistic meme that the media more often than not promotes #fakenews.