(Image: AAP/Dan Peled)

Anyone rushing to examine the list of submissions about extremism to the Parliamentary Joint Committee on Intelligence and Security will be sorely disappointed. There are no great, novel insights.

But the inquiry into radicalisation, prompted in part by Labor's Kristina Keneally, serves to highlight threats both known and not so known. It may be dwelling on the fringes, but there is no doubt that dangerous extremism is alive and well in some quarters.

Let's consider the analysis of the sources of possible terrorist threats. Terrorist networks such as al-Qaeda and their respective affiliates remain a key threat to national security. This is unchanged, almost two decades on from the tragic September 11 attack.