Caller ID sucks. It's easy to spoof and offers little in the way of genuine security or peace of mind. Microsoft's new patent, for acoustic caller ID, sounds (ha!) like a massive improvement: instead of relying on the honesty of the caller, it recognizes their voice pattern.
Even better, it's unilateral, meaning that the person receiving the call can use it without alerting the caller ? who is, correspondingly, unable to do anything to block it short of masking their voice.