No point in getting hung up on labels, or thinking in terms of some James Bond operation, with Mr Big in a fancy headquarters somewhere, and if it can be found an destroyed everything can get back to normal.

Here's a quote that makes a lot of sense to me, from an article by Richard Norton-Taylor (in today's Guardian).

"Al-Qaida is not a traditional terrorist organisation with a disciplined hierarchy like the IRA. It is used, misleadingly, as shorthand for any Islamist extremist group.

"It is more like a movement, almost amoeba-like, with varying degrees of support and contacts with other groups throughout much of the Muslim world, including Algeria, Egypt, Yemen, Indonesia, and elsewhere in the Gulf, including Saudi Arabia. But not among Palestinians, a generally secular people; and certainly not in Baghdad, home of the most secular country in the Middle East, Israel included."