PhormDiscover works by anonymously understanding your interests to show you personalised content. The free service is paid for by advertising and replaces irrelevant ads on participating websites with ones that are more interesting and useful to you.
For example, if you are interested in a particular car or camera, you could be shown an advert for that, or if you like a particular band, you could be shown an advert for their latest album. Whatever your interests, seeing adverts linked to them is more useful than seeing adverts that could be completely irrelevant to you. The advertising that you see will not increase. Existing ads will simply be replaced with ones more relevant to your interests.