(Bloomberg) — Soon, Robinhood Markets Inc.’s retail traders won’t have to leave the platform to brag about their positions or post taunting memes celebrating their investment victories. The online brokerage is breaking into social media. The move is a return of sorts to the firm’s origins. Before starting their trading platform, Robinhood founders Vlad Tenev and Baiju Bhatt planned an online community for sharing investing information. Robinhood traders have long been more active on social media than othe ...