I think as a SEO perspective, Content is still the king that bring you more customers and leads. There are two different marketing ways through the Internet.
1. Search Engine Marketing: Here, Content is the king. You generate low quality content, neither the search engine nor the people will bother to read your stuff.
2. The Social media marketing: This is where you have made a great point. Facebook with 2.2 Billion users is a hot spot for small-business to big Corp. to use it as a marketing platform by building connections.
Thank you for a great article.