Social Media is undeniably valuable but if you could make it work to improve your SEO then you could get a lot more value from it. Generally SEO and social media are considered separately and often dealt with by different people or even different departments in a company often with Social Media coming under PR and SEO being dealt with by a web designer or web master.
At the very least social media people and SEO people should be communicating and discussing what they are doing and what they are trying to achieve, if you are using agencies or freelancers then it makes sense to use the same provider for Social Media and SEO.
Several of the biggest social media sites have ‘No Follow’ links, this means that they have little value for SEO as a search engine robot is basically being told to ignore them; it is a way of saying here is this site but linking to it doesn’t mean we endorse it and we don’t want to spread Pagerank to it.
Some social media sites of course have ‘Do Follow’ links the good type that help your SEO and let Pageranks spread from other sites to yours: these sites can be used then for SEO but if everyone is abusing them you have to assume that Google will be wise to this. Those social media sites where your content will appear on a page with its own static URL will be the most useful as otherwise there is no static page for your link to be found on or it will be on a page with too many other links going off page. Choose your sites carefully and consider some very niche ones, as long as they are relevant to you.
What social media can do is help you get ‘Do Follow’ links; the way it does this is by getting the right people to see your content. Link bait content is a great way to build organic links that Google and others will see as organic hopefully and not give you penalties for or give you less value for. Link bait content is only good if people see it and then the right people; social media is your way of getting other site owners and blog owners to see your content and then potentially they will link to it. Often the same people who will retweet a link will happily put that link on to their site.
The way you approach building contacts on Social media may need to change to get this benefit but what you post won’t need to change too much as long as you regularly link to your article. With building followers, friends and contacts though you need to be courting blog owners and often even competitors or at least people in the same industry. You could even with the owners of very relevant and high pagerank sites start communicating with them more directly and let them know who you are: they are more likely to link to your articles if they have some kind of relationship with you.
Another useful trick if you or your company are keen tweeters is to get your Twitter feed to appear on your homepage using an app that is designed so that it is visible to search engines. Each time you Tweet you will have fresh content on your site that will improve your SEO as Google love to see active regularly updated websites.