Supporters of the Islamic State group are using the Internet Archive to frustrate efforts to delete their online propaganda, a study suggests.
"Much of this content is taken down promptly upon our being made aware of it, for example content with executions or personal threats," explained Chris Butler.
"Other extremist material may be sequestered and/or placed behind barriers to deter the use of our site for promotional, propagandistic purposes while keeping it preserved, which various journalists, academics, law enforcement officials, and other researchers have all let us know is important and useful in their work.
"We find that this intervention tends to reduce the number of views of these materials dramatically."
However, Mr Wolf commented that the Internet Archive might soon find itself under pressure to be more proactive.
"In late 2017 and early 2018, we saw European governments in particular discussing levying fines or taxes against hosting providers for not removing extremist content from their platforms within a given period of time," he said.
"It is not clear whether Archive.org would be included among those that might be fined, but the possibility exists."