OpenSesame, a startup that operates a marketplace for corporate learning programs, has raised a $28 million round to fuel growth. Founded in 2011, the Portland, Ore.-based company runs a marketplace similar to Amazon or Alibaba, but with a focus on online training classes for employees. OpenSesame has more than 20,000 classes hosted by hundreds of providers that teach a variety of subjects, from SEO to JavaScript to Interview Skills. The platform gives content creators an easy and efficient way to reach the masses and specifically corporations. Classes can be played in any corporate training system.