Centralized systems are almost asking to be spying on, laws or not. Even if the NSA does not have the right to do what it did, I'm sure they'd end up doing by using corruption, and there are many ways to do it. Worse, it would open the door to a lot of other shady practices, and I'm sure criminal would make a buck out of it.

The fact that a huge quantity of information is put in one place increases the risk it will peeked into by a lot.

Decentralized systems are a little more difficult to maintain and develop, but are so much cheaper and eliminate the risk of mass surveillance. There are still security risks depending on designs, but honestly I think decentralized has a lot of future, the advantages and features it brings counter balances the disadvantages by a lot.

I wish bittorrent inc would produce more technologies and some competitor would really be cool.