Earlier quoted context omitted.
The danger is that foreign governments will recognize that the US is using gmail to spy on them. They may ban the use of gmail or other cloud providers within their national boundaries.
I don't think most governments will go that far for casual usage, however I do see more restrictions on confidential, "official business" communication and storage through these (which, I hope is already the case). Think of how much disruption would be caused if Hotmail, for instance, was forbidden in addition to Gmail. Many of the early adopters of the web in these countries flocked to the most popular platforms (in…
The levels of action that a nation could take to protect itself are:
1. They could train people who have access to sensitive information not to use any US service. This is what the US has done asking some members of the intelligence community to not use Skype and other services due to worries about its insecurity. This is probably common training for handling sensitive information in most nations.
2. They could filter such services at government offices, schools and sensitive sites. For instance no company can get defense contracts unless they have a policy that prevents their employees from using gmail. This is probably the most likely additional action that will taken and it will hurt US business.
3. They could filter such services at the national level. China (1 billion people) already does this, I wouldn't be surprised if Russia started. It's unlikely to happen on a global scale but each country that bans another US service hurts the economy.
We saw this happen with US crypto export controls, the market spoke and companies began switching to non-US software.