Thankfully, Apple Computer has carefully designed their Software Update Control Panel to be courteous. By default, it is off and the user must explicitly give permission for the OS to download a system update from Apple. Things like this hardly ever get better unless laws are passed. Today, such actions by software are not, I believe, in violation of any law. This is a SETI at Home like project, probably inspired by SETI at Home itself, which will enroll subscribers.
Subscribers offer up spare CPU cycles and disk space and are compensated accordingly.
In turn, Centrata sells distributed CPU power and storage to their customers. But SETI at Home is a purely voluntary effort. You may disable and uninstall the software any time you wish, terminating your volunteer status. What if the customer is engaged in nuclear weapons research with which you disagree. You'll never know how your computer is being used.