From Eric Hutchinson:
California is in the process of trying to pass a “do not track” bill that would require companies doing business online in California to offer an “opt-out” privacy mechanism for users of those companies’ services. Google, Facebook, Time Warner Cable, CTIA – The Wireless Association, the California Chamber of Commerce and around thirty other associations and companies wrote a letter to the Senate stating the bill would, “create an unnecessary unenforceable and unconstitutional regulatory burden on Internet commerce.” If the bill is passed, consumers would be able to opt out of data collection such as the date and hour of online access, the location from which the information was accessed, the means by which it was accessed and other information collected every day by these companies. The companies call the legislation unconstitutional, because they claim it’s an appropriation of Congress’s authority over interstate commerce.
Source: "Google, Facebook: 'do not track' bill a threat to California economy," Ars Technica