Part of the Snowden revelations was that the German intelligence agency was using one of the US-developed tools in return for feeding back keyword-based searche

Part of the Snowden revelations was that the German intelligence agency was using one of the US-developed tools in return for feeding back keyword-based searches of that very same German traffic they were processing. Keywords like djihad, Siemens, Krupp, Deutsche Bank, Airbus, Santander, Dassault, ... The BND was in essence helping the NSA do industrial espionage on both their own and fellow EU companies, as they were too idiotic to actually check the keyword lists or for whatever reason felt they couldn't refuse. So if the NSA is actively and purposefully doing industrial espionage there is little doubt that Gmail traffic is vulnerable to US spying and should simply not be used in sensitive settings.