Cell phone spying

A couple of days ago, Larisa Alexandrovna addressed the federal government's acquisition of cell phone data to track terrorists and drug dealers. She argued that this spying had nothing to do with fighting terror:

Because every counterterrorism expert will tell you that those who pose any threat to our national security are not stupid enough to use cell phones that can be tracked.

Indeed. For a while now, I've been under the impression that the real hipsters in terror circles had all switched to VOIP technology, which is easier to encrypt and much tougher to track.

The advent of prepaid calling cards and the proliferation of Voice over IP telephony have made mobile phones almost irrelevant.

In a case study, a prominent telecom company A discovered that several thousand dollars worth of phone time had been purchased using stolen credit cards. Despite extremely heavy security, this company still succumbed to the effective measures of people who were clearly bent on obtaining airtime. The subsequent tracking of IP’s indicated that not only had the orders been placed using heavy IP masking, but that they originated from hacked computers and the traced ended in Lebanon. Careful analysis of the Call Records (CDR’s) indicated that hundreds of phone calls had been made using the same prepaid account to a number of high threat countries such as Ethiopia, Somalia, UAE, and a few European countries.

I've heard -- but cannot verify -- that the NSA now has the means (or soon will have) to trace VOIP usage. Perhaps a more tech-savvy reader can tell me more about this...?