"With this tech in place, the government doesn't have to put you in jail. They can do something more sinister. They can just email you a sexy picture you took with a girlfriend. Or they can email you a note saying that they can prove your dad is cheating on his taxes. Or they can threaten to get your dad fired."
With increased surveillance, the government won't have to necessarily prosecute or penalize dissidents, they can merely intimidate them extralegally. It's unlikely in the near future that we will see intelligence gathered from PRISM used in domestic courts, but it's not improbable that this collected information could be used to blackmail individuals into compliance. Think J. Edgar Hoover's secret cache of incriminating files (on such dignitaries as JFK and Eleanor Roosevelt) extended to the general public.
"that's a nice family ya got there, it'd be a shame if somethin' shoulda happen to it..."
(I tried submitting my link but I'm getting a "Please try again" error every time, so I gave up. Feel free to post it yourself.)
Thing is, we have the ability to take action right now. The author of the post on reddit is right: things like this already happen in other parts of the world. We have ways of protecting ourselves at our disposal. They're even accessible to non-techy people. People just need to recognize the events of the past couple days as an actual threat.