I'm a judge in Brazil. Even tough I'd pray to not be the one that had to give such an impopular order (affecting more then 100 million Brazilians - WhatsApp is really a hit here), we have laws in this country and we must prosecute criminals.
Mark's talk about privacy is, in my opinion, totally misplaced. No right is absolute, and that includes the right to privacy. Criminals, for example, simply don't have it. This is not me saying; this is our Constitution saying it (and the Constitution of every Western country that I know).
We are biased to see all measures against privacy with bad eyes, specially after Snowden. But that's because you are good people and see the matter with those eyes, not with the eyes of a criminal. Do you guys think that pedophiles, terrorists and drug dealers have the right to privacy ? I don't.
Also, what the NSA was (is?) doing is a complete absurd, with no judicial oversight, mass collecting everything they can get in secrecy. This has nothing to do with what we have here. In Brazil, only a judge can authorize someone to be wiretapped, it can only be done in criminal cases with jail time (no civil cases). Also, the judge must specify a single phone number or single e-mail account and the decision must be reviewed every 15 days, otherwise it expires. Also, there's a national database of wiretaps that every judge must feed by the end of the month, specifying how many wiretaps there are currently running.
WhatsApp and Facebook are not, by any means, above the law. If they want to provide a communication service here, the law is clear that they must abide by judicial orders that allow wiretapping in very specific cases.