Rich Jones wrote:

   Is there the GSM equivalent of a VPN? Seems like you could set up a
   public rotating proxy pretty easily with Asterix + DIDx..
   Just dial 1-900-MIX-ALOT - get a tone, enter the actual recipient
   number, get connected through another exit point..

     It used to be the case that people would hack PBXs and dial them in a
   sequence.  Feels like a lost art.  =/
     As for burner phones now, $10 in cash will get you a phone with ten
   minutes of talk time already on it.  Another $20 will buy you an hour's
   worth of time, and so on. No ID required.  The idea that people are
   paying $75 for a burner phone, only to totally misuse it, is annoying.
   Ideally, burner phones would be both disposable and used only for
   talking with <4 other burner phones which *also* only communicate with
   that same group of phones.  But even then, it's problematic to say the
   least.
     Social graphing cell phone users is extremely useful.  Think of your
   own phone habits.  Who do you call?  An average person might call their
   boyfriend, their best friend, their office, and maybe order a pizza.
   So how many people call those four numbers?  How many people call *one*
   of those numbers?  Less than ten on a regular basis?  Also, this basic
   social graphing doesn't even take into account one's location.  Steve
   Rambam has had a lot of great things to say about this as well:
   [1]http://vimeo.com/21590213 (from Last Hope)
     And that's how people get caught being "anonymous" with cell phones.
   ~Griffin

References

   1. http://vimeo.com/21590213