One part I found fascinating was that Silver believes the NY Times played up the letter because they were sure Hillary was going to win anyway. Plus, the tough reporting was a way to show critics that there's no ideological bias at the Gray Lady:
Why was the Times giving Comey’s letter such blockbuster coverage and at the same time going out of its way to insist that it wouldn’t affect the outcome?In testimony before Congress yesterday, FBI chief James Comey said he wishes he could have found a third way between reporting and not-reporting the fact that Huma Abedin had forwarded classified information to Anthony Weiner so they could be printed out. Either he's be accused of a cover-up, or unduly swaying the election. The ideological bubble at the Times was so impenetrable, they convinced themselves they could do some tough reporting and it wouldn't hurt their girl.
The evidence is consistent with the theory that the Times covered the Comey letter as it did because it saw Clinton as the almost-certain next president — and Trump as a historical footnote. By treating the letter as a huge deal, it could get a head start on covering the next administration and its imbroglios. It could also “prove” to its critics that it could provide tough coverage of Democrats, thereby countering accusations of liberal bias (a longstanding hang-up at the Times). So what if it wasn’t clear from the letter whether Clinton had done anything wrong? The Times could use the same weasel-worded language that it often does in such situations, speaking of the Comey letter as having “cast a cloud” over Clinton.