Bypassing blocked Caller ID

Slashdot:

TelTech, developers of the infamous SpoofCard service, have come out with something even more controversial: a set of services for revealing blocked caller ID numbers. The services take advantage of a loophole in the way caller ID blocking works — it has never been effective when calling an 800 number, because the recipient is paying for the call. So TelTech instructs you how to forward blocked calls (transparently) to their 800 number; the call comes back to your phone in seconds with the formerly hidden caller ID revealed. Advocacy groups for victims of domestic violence are concerned. Victims of annoying calls hiding behind caller ID blocking are rejoicing.