In the US courts, the phenomenon of copyleft trolls is recorded, which use aggressive schemes to unleash mass litigation, taking advantage of the carelessness of users when borrowing content distributed under various open licenses. At the same time, the name "copyleft troll" proposed by Professor Daxton R. Stewart is considered as the result of the evolution of "copyleft trolls" and is not directly related to the concept of "copyleft".
In particular, copyleft troll attacks can be carried out both when distributing content under the Creative Commons Attribution 3.0 (CC-BY) permissive license and under the Creative Commons Attribution ShareAlike 3.0 (CC-BY-SA) copyleft license. Photographers and artists who want to make money from litigation post their work on Flickr or Wikipedia under licenses of the CC-BY family, after which they purposefully identify users who violate the terms of the license and demand payment of royalties, which range from $750 to $3500 dollars for each violation. In case of refusal to pay royalties, a claim for copyright infringement is sent to the court.
CC-BY licenses require a mandatory attribution and a license with links when copying and distributing material. If these conditions are not met when using Creative Commons licenses up to version 3.0 inclusive, the license may be immediately revoked with the termination of all rights of the licensee granted to him by this license, after which the copyright holder may seek financial penalties for copyright infringement through the courts. In the Creative Commons 4.0 licenses, a mechanism was added to prevent abuse with license revocation, giving 30 days to correct violations and allowing automatic restoration of revoked rights.
Many users have the misconception that if a photo is posted on Wikipedia and distributed under a CC-BY license, then it is freely available and can be used in your materials without unnecessary formalities. Therefore, when copying photos from collections of free materials, many do not bother to mention the author, and if they indicate the author, they forget to put a full link to the original or a link to the text of the CC-BY license. When distributing content under older versions of the Creative Commons license, such violations are enough to revoke the license and bring a lawsuit, which is what copyleft trolls use.
Of the recent incidents, the story of the blocking of the Twitter channel @Foone, dedicated to old hardware, is noted. The host of the channel posted a CC-BY photo of a SONY MAVICA CD200 camera taken from Wikipedia, but did not mention the author, after which the owner of the rights to the photo sent a DMCA copyright infringement request on Twitter, which led to the blocking of the account.
Source: opennet.ru