So part of what makes this work is that it's not an index. As opposed to doing general storage of people's data, this restricts a surveillance operation to only be able to identify specific concepts.
Keep in mind the extents governments and other private enterprise would go to get their hands on this.
You will have created a clean super-weapon.
Or 'the dark mark' for those biblical folk out there.
Can you imagine what that would do to your life as well? Even if you couldn't access the information.
Half the governments of the world would torture you just to double-check.
I think that's from Harry Potter, not the bible. Maybe you meant the mark of the beast?
Its just a smart way to comb through all the data you've extracted.