Editors of the English version of Wikipedia have blocked 381 user accounts for editing articles on the online encyclopedia despite being secretly paid to do so by various interests.

The editors also deleted 210 articles created by the accounts. Most of these were generally promotional in nature and were related to businesses, people in business or artists. The articles had biased information, unattributed material and potential copyright violations, the Wikimedia Foundation that runs Wikipedia said in a blog post Monday.

The foundation said it believed the edits were made by one coordinated group because of their similarity.

Wikipedia has been struggling for a long time against so-called sockpuppet accounts, which often can be multiple accounts used by a single editor to mislead and deceive other editors. Content in the encyclopedia is created, edited and maintained by a large number of voluntary editors, but the model has proven to have limitations, including allowing the editing of information by people who are secretly paid to do so by external interests.

In 2013, for example, it said that an investigation by the English Wikipedia community into suspicious edits and sockpuppet activity had found that a large U.S. consulting company had created, edited, or maintained thousands of Wikipedia articles for paying clients. The firm had used concealed user accounts, Wikimedia said.

The 381 accounts now blocked by Wikipedia's volunteer editors were charged with "undisclosed paid advocacy".

In June last year, Wikimedia changed its terms of use to ban editing for pay, without disclosing an employer or affiliation, on any of its websites.

Editors of Wikipedia are now required to disclose their employer or client or any affiliation from which they receive a compensation. Such editors with a conflict of interest are advised not to edit articles in which they would have an interest as a result.

Wikipedia editors are referring to the current case as Orangemoody after the first sockpuppet identified in the investigation.