Terror Is Profitable
While Qwest didn’t get involved in the illegal data transfer [if it wasn’t illegal Qwest would have been forced to comply], at the time they were cash poor and made a deal with the Carlyle Group, selling them their directory publishing arm, QwestDex.
After you suck up all of those phone numbers, you want to find out who they belong to, which is trivial when you buy the directory information from the telephone book publishers. Of course, these will be classified intelligence contracts, so the public will never know about them.
This information isn’t available for the pre-paid cell phones that criminals and terrorists use, so they only have information on tax paying, law abiding citizens. [This will be changed in PATRIOT ACT III – the Empire gets Peevish when Darth Cheney orders pre-paid phones banned from the realm.]