Over the weekend, the NSA finally ended its contentious phone metadata spying program. It was first brought to public scrutiny after NSA contractor-turned-whistleblower Edward Snowden leaked documents to journalists about the scale of the US government's spying, provoking a global debate over privacy and security. Though hailed as a hero by privacy activists, Snowden is viewed as a traitor by many in the US establishment, and would face trial if he returned home (he's currently in exile in Russia.) But his leaks have provoked some political changes.