You can use your website as a way to maintain an online dialogue with your customers. An example being you could create a newsletter that contains a mixture of product news and useful tips and email it to interested people. You could build your subscriber list for your newsletter from users of your website.
It could be a good idea to have a summary in the newsletter of articles that you have put on the website. The customer is then encouraged to click through from the email newsletter to revisit the website on a regular basis when you periodically send out your latest issue be it weekly, fortnightly or monthly.
Thinking in terms of an annual programme of communications and promotions that will remind your customers about your business and the benefits of employing you, developed and deployed in the right way the results can be outstanding.