Give listeners the opportunity to easily join your newsletter.
You are the one creating great content, but you're letting the podcast players own your relationship with your listener. Instead, get your listeners on a mailing list and periodically reach out with things of interest.
Podpage makes it easy to prompt someone to sign up for your email list, and you can export the info anytime to Mailchimp or other newsletter service.
Search Engine Optimization. Your site has been obsessively optimized to rank high on a search results page.