Beginning with a February 12 inbox blast, Nike incorporated a ShareThis button to the bottom of email messages promoting its Lunartrainer+iD product line.

ShareThis enables users to share portions of an email — or website — with friends across the networks they use, giving otherwise static messages a potentially "viral" quality. It and functionalities like it are dubbed "share with your network" (SWYN) links.

News of Nike's SWYN inclusion was reported by the Retail Email Blog, which was also kind enough to provide the image at left. The act represents growing interest by traditional marketers to incorporate more dynamic and social characteristics into email, which generally tends to be one-way monologues between marketers and clients.

In December 2008, for example, Goodmail announced a service that embeds video into email messages. Silverpop has also experimented with integrating email campaigns into social networks.

The move to make email more "shareable" is also part of an across-the-board trend toward incorporating more social network characteristics into all aspects of marketing communications, including mobile spaces and static websites.

"I expect to see many more retailers add [SWYN] links over the course of this year," Retail Email Blog wrote, but added, "I added ShareThis to this blog about a month ago and the usage has been less than impressive."