In 2013, Snowden revealed the US government had illegally wiretapped the world. They were able to do this because the world is dominated by US-based tech giants and they shipped their data stateside for processing. These tech giants secretly colluded with the NSA to help them effect this illegal surveillance (the "Prism" program) - and then the NSA stabbed them in the back by running *another* program ("Upstream") where they spied on the tech giants *without* their knowledge.
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