sep 07 ABC
When al-Qaeda flew planes into the Twin Towers and the Pentagon six years ago, America's focus in retaliation was very much on Osama bin Laden's organisation and how to crush it with military force.
Now there's wide consensus among terrorism experts that that way of thinking is outdated.
Western intelligence experts and law enforcement agencies are paying increasing attention to radicalisation - the process by which people embrace Islamic extremism and in some cases, terrorism.
What they've found is that al-Qaeda as an organisation is less relevant than the organic spread of Islamist ideology via the Internet - a phenomenon that allows people effectively to recruit themselves to the cause.
As National Security Correspondent Leigh Sales reports, these developments present profound challenges for counter-terrorism efforts ...
It's no longer just about an organisation with followers who obey direct orders. It's now an ideological movement with a message spread via the Internet to whoever's interested. Or, in the words of one of Australia's most respected commentators on Islam and terrorism, Waleed Aly, it's a liquid threat ...
