Around two-thirds of consumers in the UK (63%) initially find it acceptable for websites to display ads in return for free access, but the proportion markedly declines once it is explained how their personal data may be used to serve target ads.

And although consumers are largely aware that browsing, search and purchase history can be used to display relevant ads, this does not necessarily mean they find it acceptable for the information to be shared with advertisers.

These are some of the key findings from an online survey of more than 2,340 UK adults conducted by research firm Harris Interactive at the end of February on behalf of the Information Commissioner’s Office (ICO), with additional input from Ofcom, the media regulator.

The IPO, an independent official body, commissioned the study to gauge public awareness and perceptions about how advertising is served based on their personal data, choices and behaviour.

It established that just 36% of consumers continue to find it acceptable for websites to share personal information with advertisers once they have found out more about how the adtech process works, including the type of data that websites share.

Similarly, the proportion of consumers who regard the sharing of data with advertisers as unacceptable almost triples from 14% to 43% after they gain more understanding about how the system operates.

A majority of consumers regard it to be unacceptable if websites share data with advertisers about their device, operating system and IP address (55%), unique identification codes (53%) as well as their browsing history, search history, location and year of birth (all 51%).

However, despite their clear objections to having their data shared for the purposes of ad-targeting, it appears at least some consumers want a “have cake and eat it” approach because more than half (54%) agree they would prefer to see ads relevant to them rather than seemingly random ones.

What’s more, some 59% feel that the ads they see on ad-supported, free-to-use websites seem to be personalised to them at least some of the time.

Sourced from ICO, Ofcom, Harris Interactive; additional content by WARC staff