This is the part where I say (again) that I worked in the US intelligence community for nearly 6 years. So, being the only person here (probably) who has actually stepped foot INSIDE the NSA, CIA...I think my oppinion here matters.
First off, they CANNOT do whatever they like. You have NO IDEA what the laws are like restricting surveillance, especially as it relates to US citizens. They are VERY restrictive. Beyond that, communication between agencies is also restricted, thank you Bill Clinton.
As to the information they gather. I'll say this, it ain't a crystal ball. That is the problem you see, people don't really understand how hard it is to put together a picture from the jigsaw puzzle that is global surveillance. If you ever read a report that says that intelligence sources said X is definate or Y is sure...they are not real reports. You are tought as an analyst to say things like "highly probable" or "might be"...because that is usually all you have.
