Who helped the journalists obtain that "top-secret" court order?
Hopefully, that's going to stay secret for a long time. As Charlie Savage and Edward Wyatt note in the New York Times, "The order was marked TOP SECRET//SI//NOFORN, referring to communications-related intelligence information that may not be released to noncitizens. That would make it among the most closely held secrets in the federal government, and its disclosure comes amid a furor over the Obama administration's aggressive tactics in its investigations of leaks." In other words, it was likely leaked by someone who took a personal risk exposing it.
Why? It is impossible to know. But it isn't hard to identify likely motives. Perhaps the leaker felt morally repulsed by the knowledge that the government is spying on millions of innocent citizens in secret, something normally associated with Communist and fascist regimes, not democratic republics. (It's true that the order doesn't cover the content of calls, and that a separate warrant is needed to connect the information to actual users -- not that we'd know if they sought those, or if officials now or in the future just ignored that legal requirement to spy on individuals. One wonders what Richard Nixon would've done with access to all that information.)
Perhaps the spying offended the leaker's patriotism, since it transgresses against traditional American values. Perhaps the questionable legality of the warrantless spying prompted the leaker to act.
The motive could've been the leaker's perception that secretly vesting the government with the power to know who is calling whom, when, and perhaps even from what location, invites abuses so severe that they obviously outweigh whatever legitimate benefits come from this practice.
Finally, the leaker might think that if the government is going to spy on a massive scale, it ought to be something the polity knows about and debates, not the secret machinations of a segregated ruling class doing things that would shock many who they're paid to represent.
Any of those motives would cause me to regard the leaker as a hero. If one of them explains the leak, then thank you, unknown American. May you inspire future leakers to follow their consciences when government is transgressing against basic norms of justice (and to exercise good judgment and due caution to refrain from releasing information that really ought to stay secret.) Anyone uncomfortable with the government secretly obtaining information about all of your phone calls, possibly including your physical location when you make them, should remember this case the next time Team Obama talks about the perniciousness of national-security leaks.
Some leaks are pernicious -- but certainly not this one.
There would be fewer leaks if the Bush and Obama administrations hadn't improperly hid so much of consequence from the American people, including policies that made federal employees uncomfortable or ashamed, usually because they're illegal, immoral, or at odds with American values.
As a first-term Illinois senator turned president-elect once put it, "often the best source of information about waste, fraud, and abuse in government is an existing government employee committed to public integrity and willing to speak out. Such acts of courage and patriotism, which can sometimes save lives and often save taxpayer dollars, should be encouraged rather than stifled. We need to empower federal employees as watchdogs of wrongdoing and partners in performance." Just as we celebrate Daniel Ellsberg of Pentagon Papers fame, recognizing that his leak made America stronger rather than weaker, I hope and trust we'll one day celebrate the War on Terror leakers who kept reminding Americans that their national security state is out of control.