Back in the day a single link was a sign of a website’s popularity. The more links, the more popular the site was, therefore it would rank higher. It then became a race to build the most links without a care in the world in regards to quality. Google soon developed a way to give more weight to specific links and not value them all the same.
Then people began to game that system as well and then Google began to issue penalties to sites that were mass spamming just to build massive amounts of links. There will always individuals looking to win at the link game, but social signals are the newest way to gauge the popularity and authority of a website.
It is much harder to fake “real” social signals as they come from actual users. There are many fake social signal providers but the fake accounts do not stick long and soon disappear. Make sure to get your social media following to engage with your content and website, as it will help your SEO efforts.