|found on truthdig|
It seems to me that if you collect everything (and apparently the NSA and GCHQ do just that) then you're going to have a heck of a signal-to-noise problem to overcome. Spam and other malicious email makes up an outrageous proportion of the email traffic in the world and they need to be able to ignore that junk. Imagine the amount of money they must have thrown at that problem over the years. I wonder if there's anything they could teach us about filtering out junk.