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.
Tradedoubler was founded in 1999 by two young Swedish entrepreneurs. They have offices in the UK and multiple countries throughout Europe, including Sweden, Germany, France, Poland and Spain. Their focus has always been to provide smarter results for both clients and affiliates through technology. In 18 years, they’ve amassed an army of 180,000 active publishers, connecting them to over 2,000 merchants in Europe and the UK. Many of these merchants are household names.