It is probably one of the most significant factors in search engine rankings today. Many content marketing services
develop different strategies to provide you with the best content. If you have good content to share with the world, chances are the wind will carry it a long way - but still nowhere near as far as proper content distribution would! It's one thing writing a beautiful blog post all about a particular subject that people could find useful - it's another going around forums, social media sites, and Q&A websites to build up a following around your brand/site name so when people search for it, they get results from more than just Google or other directory listings.
If nobody's going to find your website in the SERPs, it doesn't matter how well optimized it is for its primary keywords or how attractive a turn-off page design is - no one will ever see it! You need traffic from people to lay your site bare in front of, and without that, search engine rankings are mere hollow statistics. Once again, driving targeted traffic isn't easy, but there are ways and means to get it done.
Social media sites today have become a big part of life online. People often use them as a starting point when searching for information or solving a problem. A strong social media presence helps drive up your SEO simply because it helps drive traffic to your website, which you can then convert into customers/leads etc.
Do you know if the search engines properly index your site? Whether it's overflowing with errors that have gone unnoticed or its structure has recently changed - perhaps for some reason, someone decided to move all of the pages around, insert loads of new ones in random spots, and so on - these are things Google takes notice of when indexing a site. If your site is riddled with technical errors, chances are it won't be ranked very high despite being optimized with keywords!