More than 2,000 items were earmarked for removal in a 48-hour international blitz on online terrorist content.
Europol's specialist internet referral unit teamed up with colleagues from a number of other countries to target accounts used by terror groups to radicalise, recruit and direct activities.
As a result of the operation last week, 2,068 pieces of content in six languages across 52 online platforms were flagged to service providers.
Europol, the EU's law enforcement body, said the "co-ordinated hit" focused mainly on the online production of terrorist materials by Islamic State (IS) and al-Qaida-affiliated media outlets.
Among the items referred were propaganda videos and publications glorifying or supporting terrorism and extremism.
Europol said: "The efforts made by numerous online platforms to remove inappropriate content have driven supporters of terrorist groups to simultaneously use multiple platforms to promote terrorism and incite violence.
"They have also been searching for new service providers to make sure their messages reach potential supporters.
"A growing interest for platforms that do not require identification can be witnessed.
"During this campaign, the participants identified a new platform that appears to be set up by terrorist networks themselves for not only spreading propaganda, but also financing their activities."
The final removal of the referred material is carried out voluntarily by the service providers in accordance with their own terms and conditions.
Authorities from Belgium, Greece, Poland, Portugal and the US participated in the operation with Europol.
Britain has had a specialist unit dedicated to monitoring online extremist content for a number of years.
Since it was established in 2010, referrals from the UK's Counter Terrorism Internet Referral Unit have led to the removal of more than 250,000 pages, posts, pictures and videos.
IS, in particular, has exploited the internet for propaganda and recruitment and technology giants have repeatedly faced calls to do more to stop terror-related videos and pages spreading online.