A larger portion of internet users make use of email than social media. I suppose this isn't surprising, if anything its surprising how large a portion of internet users do use social media. From a recent Mashable article:

"Private research firm Ipsos polled 19,216 adults in 24 countries last month and found 85% of them used the Internet for email while 62% used it for social networking."

http://mashable.com/2012/03/27/email-more-popular-social-media/

What does this mean for eRetailers?

Should eCommerce retailers be marketing through email, social media or both? Our assessment is this: It depends. Email and social media are totally different. In fact Facebook is different from Twitter, which is different from LinkedIn, etc.

Email is close to the ideal medium for targeting specific individuals who you have already identified. Customers and visitors who have opted in to mailing lists to receive promotions and offers, this audience is rip for individual targeting. If you can address customers as individuals, connect with them, email is the ideal medium for this.

Social media of course has its own advantages when it comes to marketing for eCommerce. Social media offers the opportunity for an offer to go viral. Using social media for marketing is all about targeting a demographic, crowd or social group. Different messages will work with social media than with email. For instance, if you are reaching out to your customers individually on their Facebook pages, saying "Buy our product.", well that is just creepy, but individual targeting is just what's needed to make your email offer stand out to a customer.