Content certainly was the most important factor for me. I cannot speak for everyone else, but I’ve heard others experience this as well.
I don’t have a strong following on social media. I have barely started to build my presence on Twitter (less than 400 followers so far and the growth has been painfully slow), my friends on Facebook came from an entirely different story and although I have around 900, most of them couldn’t care less about my blog. I’m slowly building up LinkedIn following as well but I’m far from the 500+ level, as for Google+ (less than 100) and Pinterest (135 who never click the links to my posts), these don’t really work for me.
That’s all I have to work with. It was always the content, people who have far more followers than me have liked and shared my posts, Medium sometimes pushed some of them, publications helped, some of them went viral for whatever reason and that’s how I came from zero to where I am now in less then a year. I’m completely broke, so I surely didn’t pay for any of it.