In 2020, many Americans will get a powerful tool to protect their online privacy. A sweeping new law will require millions of businesses to tell consumers what data they have collected about them and, if asked, to delete it.
The law, known as the California Consumer Privacy Act (CCPA), could play havoc with the online economy, since so many companies—from tech giants to ordinary retailers—rely on targeted ads. If people demand that companies delete their data, those ads would be less effective.
