Dark social sounds like some ominous place hackers roam and illegal transactions happen, but this is not the dark web. Dark social has to do with social sharing of brand content that's hidden.
Five years ago Alexis Madrigal coined the term dark social in The Atlantic. Some sharing of brand content is public and can be tracked, while other times sharing happens privately. In 2012 Madrigal estimated that around 69% of social referrals were 'dark' - this was 44% of The Atlantic’s social traffic, and 18% of total referrals. And today dark social is growing.