Instinct Entertainment
According to the authors “WP Campaign Monitor is an email newsletter / SMS tool built for WP users who want to send campaigns, track the results and manage their subscribers. Version Two will integrate with e-commerce lite.” I haven’t tested this, but there very well is a demand for such plugins, especially for those developing WP more as a CMS. While there, checkout the e-commerce plugin. A lot of development has been done since its first introduction.