If the NSA revelations are anything to go by, the only difference between "not enough data" and "too much data" is that the after-the-fact investigations are no

If the NSA revelations are anything to go by, the only difference between "not enough data" and "too much data" is that the after-the-fact investigations are now a bit easier. There doesn't seem to be a "Goldilocks" amount of data. Or if there is, intelligence services seem to have no interest in finding it if it means restraining themselves.