A parliamentary committee has warned that the internet is a "fertile breeding ground for terrorism", posing more danger than extremism on campus.
MPs have found that online activity is influential in almost all instances of violent radicalisation, yet it is not sufficiently monitored for counter-terrorism purposes.
The nine-month investigation by the Commons Home Affairs Select Committee concluded that the web was "now one of the few unregulated spaces where radicalisation is able to take place", representing a greater risk than prisons, universities or places of worship.
"There is seldom concrete evidence to confirm that [universities or prisons] are where they were radicalised", the report said.
One member of the committee, Cardiff MP Alun Michael, said that during the investigation "one Muslim said to me that 'you should worry more about Sheikh Google than about what's happening at the mosques'.
"That fits with the evidence that we saw that the mosques, by and large, are not the places of radicalisation and nor are universities."
The report called for internet service providers to be more vigilant in monitoring online activity.
Although the report acknowledged that face-to-face interaction with radicals was a "significant factor" in radicalisation, the authors said that a code of practice for removing such incendiary material from websites should be developed.
Mr Michael also cautioned that the threat of far-right extremism should not be overlooked.
Keith Vaz, committee chairman, highlighted the conviction of four men who plotted attacks on two rabbis and the London Stock Exchange. He said this reminded people that "we cannot let our vigilance slip".
Mr Vaz added: "More resources need to be directed to these threats and to preventing radicalisation through the internet and in private spaces. These are the fertile breeding grounds for terrorism."
He also called for the government's Prevent strategy to counter extremism to be renamed "Engage" to encourage a positive approach.
A spokesman for the Home Office described the report as interesting and said the findings would be considered.
"We are working closely with the police and internet service providers to take internet hate off the web," they said.
But civil liberties campaigners from the group Big Brother Watch warned that "this kind of censorship not only makes the internet less secure for law-abiding people, but drives underground the real threats and makes it harder to protect the public".