In fiber optics, the cable is a light pipe or waveguide, into which you inject light. If a finger presses on the pipe, it disrupts that light within the waveguide.
Multi-touch sensing was designed to allow nontechies to do masterful things while allowing power users to be even more virtuosic.
The funniest thing is that now I know what reverse spam is. You know you get spam from people saying, 'Can you invest in this or that?' People are now e-mailing me saying, 'Oh my God, can I invest in your company?' It's a reverse solicitation of money.