The Atlantic has a fun article about “Dark Social“. The gist of it is that good portions of the web is shared via emails and direct links. In other words, sharing that’s hard to measure.
One implication:
There are a couple of really interesting ramifications of this data. First, on the operational side, if you think optimizing your Facebook page and Tweets is “optimizing for social,” you’re only halfway (or maybe 30 percent) correct. The only real way to optimize for social spread is in the nature of the content itself. There’s no way to game email or people’s instant messages. There’s no power users you can contact. There’s no algorithms to understand. This is pure social, uncut.
Write interestingly.
