As the FBI announced that it had reviewed the emails on Anthony Weiner's laptop and determined that there was no incriminating material about Hillary Clinton on them, the Trump campaign roared with incredulity, insisting that it was inconceivable that the FBI could have vetted 800,000 emails in 8 days.
Jeff Jarvis tweeted to Edward Snowden to get an expert opinion: "how long would it take the NSA to dedupe 650k emails?" and Snowden answered, "Drop non-responsive To:/CC:/BCC:, hash both sets, then subtract those that match. Old laptops could do it in minutes-to-hours." In other words, get rid of all the emails unrelated to Clinton (because they're not from or to anyone associated with her), then use a quick hashing tool to find emails that were already reviewed as part of the earlier investigation.
This leaves a presumably tiny set (because we're only interested in emails that traversed Clinton's illegal mail server, and those emails have already in large part been reviewed by the FBI), that can be combed through by hand pretty quickly — especially as standard forensic tools are applied, such as ignoring whole threads once they have been determined to be irrelevant to the investigation.
Speaking of speculation, a conspiracy theory immediately popped up on Twitter after Comey issued his letter. The bureau took about a week to comb through 650,000 messages amid all of the unsavory flotsam that surely resides on Anthony Weiner's laptop. This was a lighting fast result, but was it too speedy?
Trump enthusiast General Michael Flynn — who was last seen declaring that Mark Cuban was "not a legitimate person" — questioned how Comey and his staff could possibly dig through an average of one email per second. He tweeted that this was "IMPOSSIBLE," and "something does not jive."