The above link is to a document of about 9 pages which gives a good historical overview of where the current jihad is coming from. It clearly shows the difference between Muslims in general and the minority of the jihadists. Their real goal is to re-establish the caliphate.
This is very helpful to know, because in the aftermath of terrorist bombings, some people are saying that this is because of US policy in Iraq, or the Mideast in general, etc., etc. In reality the jihadists would still want a jihad even if US policy was different, because this is a war that goes back centuries.