Using Social Media to Build Links for SEO
In order to request a link from a website, first you have to find it. Social media tools exist that make this task a lot easier than it used to be. Tools like Followerwonk and WeFollow help identify influential social media "influentials" around your topics of interest. These folks usually have websites with great link equity.
Once you've found your outreach targets, get to know them a little before trying to ask for a link. At first, this means doing your homework. Take prospects and look them up on Klout to see what they're known, who they influence, and who influences them. Seek first to understand, then to be understood.
The normal process for requesting links is to craft a personalized email to your prospect and hope they return your email. Increase the odds of a response with social media by friending/following them on social networks and/or sharing their content with your network before your write your email. It's easier to get a response from someone if you've retweeted their work than if you're just a stranger begging for a link.
Pinging and Warming
If you're doing it right, you're not just building links. You're building relationships. Acknowledge those who have linked to you in the past by regularly sharing their work and engaging with them on social media. Watch a simple link request blossom into a great partnership, and you'll instantly understand why link building through social media is a better long-term approach to this critical SEO activity.
Social Content Exposure
In the end, a strong social network is the best link building tactic. When you create new content, people need to see it before they can link to it. Publishing your content to your social media networks is a great way to gain attention to your work early on and hopefully earn some links right out of the gate.