According to Statistica, 76% of the U.S. population has at least one social networking profile and by 2020 the number of worldwide users of social media is expected to reach 2.95 billion (650 million of these from China alone). Of the social media platforms, Facebook is by far the most dominant - as of the end of the second quarter of 2018 Facebook had approximately 2.23 billion active users worldwide (Statistica). Mobile devices have become the dominant platform for Facebook usage - 68% of time spent on Facebook originates from mobile devices.
In addition to measuring your website traffic, you need to track your conversion rates. For example, if, as a result of your search engine marketing efforts, your traffic doubles from 250 to 500 visitors per month, how many new customers did you acquire from the additional 250 visitors to your site? Do you now have twice as many customers as you did before? If you picked up 5 customers your conversion rate would be 2 percent of the new traffic (5 divided by 250) and 1 percent (5 of 500) overall.