If you have a business that is actively on the social media sites then you may wish to consider adding a blog to your site. A blog is essentially a list of articles or stories that have been published by the website owners, and contains useful information they think their visitors may find interesting or useful.
When using social media sites, the idea is to be quick and to the point. Often with many of the sites you have a character or word limit only allowing you to post minimal content. If you add a blog to your site, not only will it help with your search engine optimisation it will also allow you to add complete articles and then share the link on the social media sites (staying within the character limits set). This also draws traffic to your website rather than just your social media pages.