Titled "Cisco Support for Lawful Intercept In IP Networks", the IETF draft describes a mechanism to provide for "Lawful Intercept" (read wiretapping) in VoIP networks.

Although it is supposed to only be used where authorized by legal authorities in a jurisdiction, significant questions arise on the internet where phone calls may pass through jurisdictions without the user's knowledge, and where the technology makes it easy for these types of behaviors to be done on a massive scale.

Here is some food for thought:

• 250GB hard drives (FireWire) available for <$400 retail at CompUSA.
• Voice can be reasonably recorded at 4-8KHz with 8 bits of resolution, thus 4-8Kbytes/second.
• Inexpensive software and hardware raid can easily achieve 80+MBps of throughput to a disk

With these kinds of numbers, you can store ~750 call-days worth of calls for $400 (storage cost). I think that the former Stasi (East German secret police, notorious for wiretaps and monitoring citizens) or current Chinese intelligence would be more than delighted to have a technological hand in tapping many simultaneous phones using cheap and easy hardware by having a common intercept broker, don't you?