"Apple simply does not use the TPM hardware," Singh wrote in his book. He told eWeek that the TPM is an opt-in feature and that "Apple can't just turn it on -- nobody can, other than the user." It's possible for individual users to take advantage of the TPM in their Mactels, and Singh has written a TPM device driver for that purpose.

Trusted Computing (commonly abbreviated TC) is a technology developed and promoted by the Trusted Computing Group (TCG). Advocates of the technology claim that it will make computers safer, less prone to viruses and malware, and thus more reliable from an end-user perspective. They also say that Trusted Computing will allow computers and servers to offer improved computer security over that which is currently available.

Opponents believe that trust in the underlying companies isn't deserved and that the technology puts too much power and control into the hands of those who design systems and software, according to [url=http://en.wikipedia.org/wiki/Trusted_computing]Wikipedia[/url]. They also believe that it potentially forces consumers to lose anonymity in their online interactions, as well as mandating technologies that many have no pressing need for. Finally, TC is seen as a possible enabler for future versions of document and copy protection, which are of value to corporate and other users in many markets and which to critics, raises concerns about undue censorship.

You can read more about TC and TCG [url=https://www.trustedcomputinggroup.org/home]here[/url]. And you can check out an argument against TC [url=http://www.gnu.org/philosophy/can-you-trust.html]here[/url].