COLOGNE: A German start-up that designs the software for Adblock Plus, the world's largest online ad blocking service, has been paid by Google and other major internet companies to unblock ads to their websites, it has been revealed.

According to a report in the Financial Times, Google, Amazon, Microsoft and Taboola, a content marketing platform, have negotiated confidential deals with Cologne-based Eyeo to get around its ad blocking tool.

With more than 300m downloads and 50m monthly users, Adblock Plus claims to be the world's most popular browser extension and that the company "exists to save its users from annoying ads".

By quietly paying Eyeo to stop ad blocking, the tech giants have demonstrated that they see the growth of ad blocking as a material threat to their revenues, the Financial Times alleged.

Google, Amazon and Taboola declined to comment on the report, but Microsoft, whose Bing search ads have been unblocked, said it champions consumer choice.

"Microsoft will always give consumers choice when it comes to advertisements. We are committed to working with partners who share our vision for relevant, impactful brand interaction and respect for the integrity of consumer choice," Microsoft said.

Eyeo and its Adblock Plus tool do not block all ads, but instead operates a policy of "whitelisting" whereby large websites pay a fee to participate in its "acceptable ads" initiative that serves non-intrusive ads.

Whitelisting is free for small- and medium-sized websites, the company says, while Adblock users who disagree with its decisions about which websites to whitelist are given the option of blocking all ads or to move to other ad blocking providers.

A study released last year by Pagefair, the Irish technology firm, found the number of people around the world who have installed ad blocking software had increased 69% to about 144m, or 4.9% of all internet users.

Written in collaboration with Adobe, the software multinational, the report also found that 27.6% of internet users in the US claim that they employ adblock software when browsing.

Data sourced from Financial Times; additional content by Warc