The recent trend in e- mail marketing is integration of social sharing. This functionality enables sharing the content of your email via facebook, twitter, google+, linkedin etc. Interestingly, it comes complete with tools to track analytics like page views of the email and linkages to the social media site as a result of the emailed content.
Marketers are going to find this useful as instead of having to deal with both - an email marketing service and a social media management tool - one easy to use interface can do the job of both.
My Emma, Constant Contact and Vertical Response are some of the companies that allows you to click a button 'add social sharing' while you are creating your email. When your customer clicks the button - it takes them to your company's social media page where they can like and share information about the company or a particular product.
Services such as iContact allows you to choose the section of the emailer which you would want your audience to share - could be the entire message or just a section.
Mail Chimp is really cool.They even allows merging of youtube merge tabs that can help incorporate videos in your email marketing message.