Here's a video of Gary Vaynerchuk, a person who many, including me, admire as the king of social media, saying that social media doesn't pay unless you're staying up until midnight every night engaging people and are willing to continue that for up to a year without seeing any ROI.
Gary cites a client study as his most demonstrable ROI story. He took them on, assuming all aspects of their marketing, and in one year was able to deliver a 9% increase in sales, mostly by impacting their brand through social media.
Now, a 9% increase isn't necessarily bad, but it's not hockey stick either. And when you consider all the super impactful growth strategies - aggressively hiring and managing top sales people, doubling down on key client visits and ppc to name three - 9% is not a whole lot.
And remember, this is Gary Vaynerchuk we're talking about. The king.
Agree with me or not, the video is quite entertaining: