The NSA only affects the USA, right?
Nope. They have the ability to access data on anyone in the world if they are using online services and programmes that are based in the USA.
Any information you give or use on Google, Apple, Skype, Facebook and any other company that is based in the US is available for the NSA to view. Whether that's via PRISM, where they have direct access, or whether they have to go the longer route where they request access and have to be given it.
Either way, any data you put in the hands of a US company is now available for the US government to access.