I use and have used em-dashes my entire life, including online e.g. on Reddit, Slack, and here. My wife and numerous friends our age do the same. Among those

I use and have used em-dashes my entire life, including online e.g. on Reddit, Slack, and here. My wife and numerous friends our age do the same. Among those who studied English at e.g. a college level it's a natural and not uncommon part of professional writing... even online. At least for those of us old enough to still punctuate and capitalize our texts.