Mario Ruiz, the head of communications at the Huffington Post has left the company amicably. Ruiz was the one-stop shop for the Huffington Post’s media operations (think press inquiries) and PR. He is became well-known during his tenure at HuffPo, and will be using this popularity to start his own marketing firm. First client? The Huffington Post. While some PR people and marketers drive people crazy and are disliked by some, this firm will be one to watch in particular.