Google is to pay computer users to browse the web so the search giant watches every link they click.
'Panelists' in the new Google Screenwise programme will be paid up to $25 in Amazon gift cards.
The payments offer an insight into how much web users' private data - usually harvested by giants such as Facebook and Google without payment - is worth.
Users have to download a browser extension, which allows Google to monitor which sites they visit and how they use them.
'Even though this Screenwise program is completely opt-in, some critics are bound to question why Google needs more data about web searchers and the websites they visit.'