These are important if you’re trying to get more visitors (hits) and conversions on your website.
When a lot of people consider a website to be an authority in its niche or a popular website, they naturally link to it. When someone links to your website, that is known as a “backlink”, and the more backlinks you have, the better it is for your Google search rank. If you get a ton of bogus backlinks from crappy people or get a robot to do them, Google may penalize you and even practically ban you from showing up on Google search all together. If government (.gov) and education (.edu) websites are talking about you (these are considered more important people), then it will boost your search ranking significantly more than just some random Joe posting a backlink. So, quality definitely matters, and so does quantity.
Social impressions are very basic… you want more people to see your stuff, right? An impression is every time your stuff appears in front of their eyes, on their screen.
When a few .gov websites linked to my website Fantasy Couch, it tremendously helped our Google rankings.
Backlinks are important for establishing Domain Authority DA is important for page ranking. (Not always but it definitely helps) With a high rank you receive more traffic. The first page of any google search result gets 91% of the traffic. 35% goes purely to the #1 rank. That’s why SEO is a market because it can bring traffic. While some argue that Social Impressions do not drive SEO results one thing Social Impressions definitely do is drive traffic which is the end all goal of any SEO campaign.