From the sound of things, it looks like customer connections are still strongest with opt-in emails and website promotions. While social media (Facebook, Twitter, Pinterest and YouTube, blah, blah, blah) do add marketing and promotional value, research shows that the top ways consumers find out about special promotions is through company web sites and email alerts. Best practice for business is to make sure your email is smart phone ready as more email is read via mobile than on a desktop or via web mail.
Stats say 43% of email is now opened on a mobile device. Litmus –”Email Analytics” (December 2012). Before you go all “responsive development for m commerce on your biz” read this http://mobile.smashingmagazine.com/2013/01/18/assumptions-about-mobile-to-reconsider/ about the assumptions made about designing for e-commerce @smashingmag