Wikipedia has launched a new investigation of "non-neutral editing" on its website, blocking or banning more than 250 user accounts for a mixture of offences, including being paid to write Wikipedia articles promoting companies or products, and not disclosing conflicts of interest.

The crackdown follows recent media coverage of what Daily Dot called "the largest sockpuppet network in Wikipedia history" – sockpuppet being the term used to describe an online identity used for purposes of deception (yes, Wikipedia).

The Wikimedia Foundation's executive director Sue Gardner revealed more details of the investigation in a blog post, criticising "paid advocacy editing" by Wikipedia users, while pointing out that sockpuppets violate the site's terms of use.

"At this point, as reported, it looks like a number of user accounts — perhaps as many as several hundred — may have been paid to write articles on Wikipedia promoting organizations or products, and have been violating numerous site policies and guidelines, including prohibitions against sockpuppetry and undisclosed conflicts of interest," wrote Gardner.

"As a result, Wikipedians aiming to protect the projects against non-neutral editing have blocked or banned more than 250 user accounts. The Wikimedia Foundation takes this issue seriously and has been following it closely."

Gardner also admitted that paid advocacy editing by PR companies and individuals has been "a divisive topic inside Wikipedia for many years", and warned that the Foundation "will have more to say in the coming weeks" on its plans to further crack down on the practice.

"Unlike a university professor editing Wikipedia articles in their area of expertise, paid editing for promotional purposes, or paid advocacy editing as we call it, is extremely problematic," she wrote. "We consider it a 'black hat' practice. Paid advocacy editing violates the core principles that have made Wikipedia so valuable for so many people."

Wikipedia claims to attract 500m readers, making it one of the most popular websites in the world. The not-for-profit Wikimedia Foundation employs 150 staff to manage the site, including legal aspects, although the moderation is handled by its community.