Ideally, email marketing should go hand in hand with social media. Adding social media "Like" or "Share" buttons to your marketing emails gives an additional way for customers to connect with your brand. Snippets of positive reviews from social media fans can be included in emails, and conversely, social media postings can be used to encourage fans to subscribe to your email newsletters.
This relationship can take multiple forms. You may partner with a brand launching a specific product and receive a percentage of the revenue generated by your referrals. Or, if you work with websites like Amazon, you receive a percentage of whatever purchase a follower makes through your referral links, even if they don't buy the product you were specifically recommending.