Zaarly's has 500,000 members, who have completed $30m worth of tasks

"Most people who have heard of Zaarly know it as a service that allows users to posts tasks for others to fulfill, such as babysitting, odd jobs, errands and the like, as well as the price they're willing to pay. Now, the San Francisco-based startup is opening up its service to retailers and publishers, allowing visitors to the Los Angeles Times, Ikea Hackers, Everyday Health to post tasks to Zaarly without ever leaving those sites.
The service, "Zaarly Anywhere," is being pitched as an opportunity for publishers to earn revenue from the inspiration they create. Zaarly's half a million users have already completed $30 million in requests and some of these projects were no doubt inspired by content created by a publisher or online retailer."

Source:  AdAge, 17th July 2012