I know, email marketing is not trendy. But guess what? It is still very effective. My email marketing efforts generate the most business of all of my marketing efforts.
According to Entrepreneur magazine, used appropriately, e-mails can drive conversations and engagement through social media and other channels. They recommend that every message should be sharable and should include a specific call to social action. However, IMHO, people rarely share newsletters, so I am somewhat skeptical of their advice.
They also suggest that you cross-post pieces of e-mail content across a variety of media in order to keep the conversation active.