If you have your own website, or are planning to create one soon, in the course of your research you will have read about the importance of publishing an ezine (electronic newsletter) as a way of generating traffic to your site.
— Note to purists: yes I DO understand there is, strictly speaking, a difference between ezines and electronic newsletters but for our purposes it doesn’t matter so don’t write me. ;)
It’s good advice. By capturing the email addresses of your site visitors (via an ezine sign-up form at your site), you can develop a mailing list to put yourself before time and time again, unless and until they ask to be removed. The idea is that by regularly sending your ezine to your list, your site visitors get to know you and, over time, come to trust you as an expert in your field. Assuming you do competent work, that is.