The Huffington Post was breezily dismissed as Arianna Huffington’s vanity play when it launched in 2005. But it proved doubters wrong by building a massive online audience with traffic-building practices and a focus on data that other web publishers still follow today. Ten years in, it led the pack in digital news sites (and also topping many legacy news sites in terms of digital traffic.) The site also went on a hiring spree to beef up its hard news and investigative coverage. With its unparalleled scale and ad formats that looked like editorial — the term native didn’t exist yet — it was undeniably a trailblazer.