Users of the site will be rewarded with cash or vouchers for a range of products in return for their input on advertising campaigns, design, new product development and seeding activity.
Unilever and Carphone Warehouse have signed up for the service.
Andrew Needham, co-founder of Face, said: "This is instant access to thousands of young people who are notoriously difficult to reach through traditional marketing methods.
"Headbox can help brands, companies and organisations harness the ideas, the activity and creativity of young people throughout the entire marketing process."
The initiative has been endorsed by advertising agency Farm. Robert Smith, managing partner of Farm, said: "Headbox will become an essential part of any brand's toolkit for targeting a younger audience. It has the potential to become the 'holy grail' for youth marketeers -- a research and insight methodology that can simultaneously begin the process of seeding and building brand advocacy."