From the UK Competition Commission's report on digital advertising: "The available evidence suggests that the user data used for targeting digital adverting is

From the UK Competition Commission's report on digital advertising: "The available evidence suggests that the user data used for targeting digital adverting is highly valuable to advertisers and publishers. For example,Google ran a trial in 2019 to compare the revenue publishers received from personalised advertising with revenue from non-personalised ads. The results indicate that UK publishers earned between 50% – 65% less revenue when they were unable to sell personalised advertising but competed with others who could."