Need help on how the world has changed since 9/11

1. How has the world changed since then as a result of the attack. Give changes from different perspectives, such as political, social, economic.

2. What measures have the countries around the world taken to prevent such an incident from happening again.

I gave him some materials based on what I read in media and what I could find from Internet. But the problem is that Internet contains various different points of view - one often contradicting another. Also, I am not sure how authentic some website is.

I need web pages, which answer the above questions in easy to understand way. Also, the web sites should be of reputed organisations.

Also, is anybody aware what is meant by "IBL" question?