The “freemium” model is getting more popular for subscription sites because it incentivizes people to sign up by giving them a taste of what they could be getting. Basically, a freemium site will provide a relatively small percentage of the benefits the site has to offer for free, and require a subscription if users want to increase the amount they can do on the site.
Many online dating networks are actually good examples of freemium sites. Most allow users limited access, such as browsing around and finding the profiles of people they might like to meet, but require them to subscribe if they actually want to contact someone and strike up a conversation (that could ultimately lead to a date).
According to some studies, the percentage of site users who actually upgrade to the subscription services for a freemium site is low—about 2%. Basically, that makes success in the freemium world a numbers game—2% of a large number is a large number. If your total traffic is only 100 visitors per month, then 2% of that would be two subscribers—not enough to build a business. But if you're getting a million visitors per month, then 2% is 20,000 subscribers—and that's a different, and more profitable, story. And for everyone else who's not subscribing, you can still generate some revenue by placing ads on your site (see Part 3 , “Generating Revenue Through Online Advertising”). The ads should, for the most part, go away (or at least be more limited) when someone subscribes.