List building services are services that help build and manage email lists of your blog visitors. With a list building service, businesses can obtain customer information, specifically email addresses. List building services combine automated or triggered email campaigns to send personalized messages or emails to the list. Simply put, a list building service is a Content Management Service [CMS] that stores all the emails you collect into a list. You can then create automated or triggered email campaigns to send personalized messages or emails to the list.