Although most people ignore it, Social Media is an unalienable part of website SEO. Social shares are always counted while calculating the rank of your website. I learned this through SEO tools that never fail to show the number of social shares while auditing a website or analyzing a search query.
If more users on social media are talking about your website, it will attract the attention of search engines like Google. Notice the three right-side sections where Facebook, Pinterest, and Reddit shares are visible.