28. Subscription – If you think of something valuable (newsletter, online magazine, etc.) that you can consistently offer on a certain basis (weekly, monthly, etc.), you may want to offer a subscription service. This could be a fee charged each time your product is sent out or on a monthly basis. Either way, this has to be something that your customers can only get by subscribing to your website.
Mechanical Turk: Amazon's Mechanical Turk is a resource for doing human-intelligence tasks, or as the site commonly refers to them, HITs. You get paid a very small fee for any given HIT and you'll need a good deal of volume to make a substantial amount of money. But it is a resource you can use in your spare time to generate a small income online.