Kevin, you say that, "I doubt if safe havens are particularly important for an "organisation" made up of disparate cells." and that Al-Qaeda has, "No need for a central command at all."

What about:

1. Training?

2. Finance?

3. Procurement?

4. Planning?

Doesn't work if everybody just bimbles about doing their own thing, particularly if the world and its dog is aware of the potential threat and is watching for it. For it to be effective it has to be organised.

Out of interest - What were the cultural changes in the west that caused the demise of the groups mentioned.