Dark Social are those visits of unknown origin, that we don't know where they come from. We could say it is invisible traffic for analysts.
This video explains the concept really well:
Measurement is a fundamental part of inbound marketing. Knowing the user in depth, testing the actions we take to make him fall in love and even knowing where he comes from, how he got to us is the basis of a successful inbound marketing strategy. The problem is that we can't always know everything we would like to know about our user.
Although this term may sound negative, the truth is that it's not a big deal, Dark Social is just the name we give to the visits of unknown origin that a website has. We call Dark Social the web content that is shared on the web in ways that are difficult to measure by traditional means.
Some examples would be content sent by e-mail from one user to another, chats, mobile applications or text messages from a cell phone. By not transmitting data, measurement becomes mission impossible.
The traffic generated by these sources varies depending on the sector and the user profile, but it can be more than 50% of the traffic of some generalist webs.
The Dark Social is important not only because of its volume, but also because in many occasions it is a traffic that comes from a contact or reputable source and visits us after a recommendation or mention.
Google analytics shows it as "direct traffic", but in most cases it is not someone who has written the entire address. According to the studies carried out in this regard, a quarter of the visits to our blogs would come from the Dark Social.
As we see, even web analytics is not an exact science. Therefore, we will have to be exhaustive in measuring our Inbound Marketing actions in order to get as close as possible to our user and to know him more and better every day.