Speaking as a writer and blogger, I can say that this has absolutely been the case for me over the past year. Whereas before I used to blog about anything that came to mind (that wouldn't negatively impact my employment), I now weigh each blog post, Facebook post, tweet ,and non-OTR encrypted GChat (for friends who are too lazy/clueless to install OTR) carefully, employing an amount of self-censorship that I never would have thought possible before. I am even now different over text messages. I've lost my writing voice.
I was afraid to write even this post [1], which sounds ludicrous, but it's amazing how much hearing the revelations impacted me.
The irony of this situation is that, even before the Snowden leaks, I had been (and am) working on a novel about 1936 in the Soviet Union, the year before the largest of the Great Purges, and had been struggling to get a handle on how people felt about information censorship and how people found out that their government was not what it seemed.