One item in Jack's post on the upcoming leak investigations caught my eye -- he noted that "It is hard to discover leakers without access to journalists’ testimony or notes (which are hard to obtain)."
My sense is that this is increasingly becoming less true. Indeed, I had one rather high-level IC member tell me, roughly 6 months ago, while discussing another matter, that he thought that there would never again be a subpoena to a journalist for his/her notes, of the sort that landed Judith Miller in jail for contempt of court during the Plame investigation. His underlying reasoning made sense to me:
The suggestion is that the era of Big Data applies to journalists too. As they pursue stories they leave digital tracks (what Gary Kovacs evocatively calls "bread crumbs in the digital forest") in the broad domain of cyberspace. Journalists, like everyone else, make phone calls, send emails, and travel in cars that may have GPS trackers on board (voluntarily with On Star, say). They download files with meta-data that can be analyzed. They have bank records reflecting credit card payments for cab rides. Etc. In short, his thesis (which as I say resonates) is that the increasing capacity of data analytics and the pervasiveness of data availability make it likely that a journalist can be tracked quite readily through his digital trail -- and that in doing so, his source might be identified even without the need to subpoena his notes.
That's not to say that such a wholesale examination of the Times journalists' records will be authorized, but it does suggest to me that the era of journalist subpoenas may be coming to an end. Unless, of course, journalists go back to meeting sources in underground garages.