I can't speak for nodesocket, but I noticed the $SYMBOL convention become popular to denote a ticker symbol when Twitter started treating $SYMBOL as a hashtag (

I can't speak for nodesocket, but I noticed the $SYMBOL convention become popular to denote a ticker symbol when Twitter started treating $SYMBOL as a hashtag (often called a "cashtag") a few years ago. https://twitter.com/twitter/status/230098997010911233 https://twitter.com/twitter/status/230098997010911233