So, per person on the planet, that would be 10^24 / 7*10^9 ... lets say on order of say 10^14 or 100 Terabytes, or 25,000 DVDs worth of storage.. for each man woman and child.
That would be enough to store a few years of everyones life in considerable detail : videos, photos, phone audio, GPS, financials, dna, web surfing, ...
You would probably need to take the complete visual and audio stream that went into a persons eyes and ears over the course of a year of their life, to start to fill that up, and do that for every living person.
I just wonder how much of that data they really need to sift through, in order to find likely terrorists ?