While membership and dating sites can be a great subscription revenue Model, they have their own unique challenges as well. One of those challenges is having high user engagement on the site. After all, your members are your content creators and the reason why new members join, so if no one’s using the site, you’re sure to go under.One way ExpertClick — a membership site that connects journalists and topical experts — motivates its members by providing them with tips for how to best use the site and succeed in their own careers. Publisher and founder Mitchel Davis says that this has been hugely influential in increasing member engagement and retention. When talking to him on the phone last week, he mentioned that a downloadable PDF is often the best format and method of delivery.To find out how to target the right members (hint: stop trying to engage users who will renew but never be active), and other helpful tips, you’ll want to hear Davis speak at the Subscription Site Summit in San Francisco next week. Tickets are selling fast, so get yours today!