One of the reasons Zoosk's membership continues to grow so fast is that they give away many of their features for free.
With a free membership, you can create a decent profile, search for and view other members, and see possible matches for you.
"When you do things such as send a message, accept a connection, or express interest in someone," explains Zoosk's site, "Zoosk’s learns more about your preferences and is able to use that information to help introduce you to people who we believe you’ll be interested in." Zoosk recommends its members provide as much detail and information they can on their profiles, consistently visiting the site, responding to messages, and updating their Smart Pick™ Survey.
This highlights a big difference between Zoosk and e Harmony or Match.com: their focus is not necessarily on establishing long-term relationships or marriages, but on giving people as many dating options as possible.
Zoosk customers should be happy to see they're only paying for a subscription plan.