Wikipedia has begun naming links to its online encyclopaedia that have been removed from EU search results under "right to be forgotten" rules.
The deleted links include pages about European criminals, a musician and an amateur chess player.
The Wikimedia Foundation, which operates the site, said the internet was being "riddled with memory holes" as a result of such takedowns.
The action follow a European Court of Justice ruling in May.
The judges involved decided that citizens had the right to have links to "irrelevant" and outdated data erased from search engine results.
A fortnight ago Google briefed data regulators that it had subsequently received more than 91,000 requests covering a total of 328,000 links that applicants wanted taken down, and had approved more than 50% of those processed.
The search engine is critical of the court's decision, but has set up a page that people can use to request removals.
At a press conference in London, the Wikimedia Foundation revealed that Google had notified it of five requests involving Wikipedia that it had acted on, affecting more than 50 links to its site.
A dedicated page on Wikipedia states that they include:
- An English-language page about Gerry Hutch, a Dublin-born businessman nicknamed "the Monk" who was jailed in the 1980s
- A photograph of a musician, Tom Carstairs, holding a guitar
- An Italian-language page about Banda della Comasina, the name the media gave to a group of criminals active in the 1970s
- An Italian-language page about Renato Vallanzasca, an Italian who was jailed after involvement in kidnappings and bank robberies
- Dozens of Dutch-language pages that mention Guido den Broeder, a chess player from the Netherlands
"We only know about these removals because the involved search engine company chose to send notices to the Wikimedia Foundation," the organisation's lawyers wrote in a blog.
"Search engines have no legal obligation to send such notices. Indeed, their ability to continue to do so may be in jeopardy.
"Since search engines are not required to provide affected sites with notice, other search engines may have removed additional links from their results without our knowledge. This lack of transparent policies and procedures is only one of the many flaws in the European decision."
EU regulators have expressed concern that Google is notifying website administrators of the links it removes, suggesting this undermines the point of the law.
While the links do not appear on Google.co.uk and other versions of the search engine created for specific EU countries, they do still appear on Google.com, which can be accessed in Europe.
The Wikimedia Foundation has also published its first transparency report - following a similar practice by Google, Twitter and others.
It reveals that the organisation received 304 general content removal requests between July 2012 and June 2014, none of which it complied with.
They included a takedown request from a photographer who had claimed he owned the copyright to a series of selfies taken by a monkey.
Gloucestershire-based David Slater had rotated and cropped the images featured on the site.
But the foundation rejected his claim on the grounds that the monkey had taken the photo, and was therefore the real copyright owner.
The foundation also revealed it had received 56 requests for data about its users.
It said it had complied with eight of these requests, affecting 11 accounts. All of these resulted in information being passed to US-based bodies.
"If we must produce information due to a legally valid request, we will notify the affected user before we disclose, if we are legally permitted and have the means to do so," the foundation said.
"In certain cases, we may help find assistance for users to fight an invalid request."