How do startups actually get their content marketing to work?

[Editor’s note: this is a free example of a series of articles we’re publishing by top experts who have cutting-edge startup advice to offer, over on Extra Crunch. Get in touch at ec_columns@techcrunch.com if you have ideas to share.] 
Even the best growth marketers fail to get content marketing to work. Many are unwittingly using tactics from 4 years ago that no longer work today.
This post cuts through the noise by sharing real-world data behind some of the biggest SEO success