YouTube has removed videos by a radical American-born Yemeni Islamist cleric after complaints from the US and UK.
The site said hundreds of clips of Anwar al-Awlaki's calls to jihad violated a ban on hate speech and incitement to violence.
The move came less than a week after authorities intercepted air cargo bombs sent from Yemen to the US in a plot linked to Mr Awlaki.
The US has named Mr Awlaki a "specially designated global terrorist".
Investigators have linked Mr Awlaki to the US army base killings in Fort Hood, Texas, last year's Christmas airline bomb attempt, and the failed Times Square bombing in New York.
US officials say he is a leader of al-Qaeda in the Arabian Peninsula, an offshoot of the militant network based in Saudi Arabia and Yemen.
Free speech concerns
A YouTube spokeswoman said the company tried to balance its commitment to free speech with the need to prevent calls to violence.
"These are difficult issues," the spokeswoman wrote in an e-mail to the BBC, "and material that is brought to our attention is reviewed carefully.
"We will continue to remove all content that incites violence according to our policies. Material of a purely religious nature will remain on the site."
Last month, investigators working for New York Congressman Anthony Weiner, a Democrat, reported finding more than 700 videos in which Mr Awlaki appeared. The clips had garnered more than 3.5m hits.
Mr Weiner said there was no reason why Awlaki and others should be given "access to one of the world's largest bully pulpits so they can inspire more violent acts within our borders, or anywhere else in the world".
UK Security minister Baroness Neville-Jones is said recently to have told Washington officials that American websites hosting al-Qaeda videos inciting murder would be banned in the UK.
Mr Awlaki, an American-born cleric of Yemeni descent, is said to be on a CIA hit list authorised by President Barack Obama. In July, the US Treasury Department put Mr Awlaki on its terrorism blacklist and imposed financial sanctions on him.
US officials say Mr Awlaki helped recruit Umar Farouk Abdulmutallab, the Nigerian accused of attempting to blow up an airliner as it flew into Detroit on 25 December 2009.
Maj Nidal Hasan, the US Army psychiatrist accused of killing 13 comrades in the Fort Hood shooting last year, sought religious advice from Mr Awlaki and saw him preach in the US state of Virginia in 2001, US officials say.
A student found guilty of attempting to murder MP Stephen Timms in east London was said to have been inspired by Mr Awlaki's online sermons.