There was once a time when companies would make marketing budgets filled with numbers of how much they planned to spend, the profit they anticipated earning back from those campaigns, and what costs would incur from the various mediums they planned to advertise in. These marketers would evaluate the success of their campaigns by what their companies received in the way of profit from consumers. Effectiveness was measured by a metric that could be counted and compared with previous years.
Now that the grade school business lesson is over, throw it out the window.
Today, companies compete not only in terms of profit and sales, but often in terms of softer metrics like attention, impression, recognition and engagement (just to name a few). But do not confuse 'soft metric' with being insignificant or superfluous. The currency of the the internet is now sociability. How well your marketing campaigns perform depends on how often advertisements and brand content is shared amongst online users through their various networks and connections.
In the past, companies would pay top dollar for spots on TV, the Radio or Billboards to meet consumers where they were. That method hasn't changed, but the medium by which they can do so has dramatically. Study after study show increases in online activity by millions of consumers. Some of us never really leave the internet world, and have apps to connect us with social media every minute of every day. This gives brands the opportunity to engage with consumers in a way that they never have before. The ultimate aim of companies is to make marketers out of online users. By sharing advertisements or brand content, audiences disseminate that message through their various channels and networks, widening the sphere of influence that brands can achieve. An article in Forbes stated that a "Return on engagement can show you how well your brand is performing in terms of building and sustaining relationships with both consumers and influencers." The social playing field is wide and equalized, available to mere viewers and decision makers alike.
Advertisements have always been focused on creatively crafting messages that will connect with audiences and exert some kind of influence that leads them to become stakeholders in a product or service. That mission hasn't changed, but the frequency and manner in which they do so has. Brands need to generate more creative content that can become sharable among their followers and audiences in a memorable way that leaves them with a positive impression.
So when companies evaluate how many consumers are purchasing their product or using their service, they must also think about how favorably they are being perceived, and how much of their content is being shared across social platforms.