Zenefits just raised $500 million by giving its software away for free

With somewhere around $500 million in funding, Zenefits is now worth $4.5 billion, an impressive feat only made more so by the fact that the startup is only a couple of years old. What’s especially interesting about Zenefits is that, despite the fact that, despite being an enterprise software company, it gives away all of its software for free. So why the hell are investors so interested in it?!