So. If you're not plotting to blow anything up they don't give a flying fuck about you.
Haha, that's such a fallacy, a tired trope and to top it off - not even true.
For example, NSA database (the very same one collected by wiretapping everyone in the world) has been used by the DEA to investigate things that have absolutely nothing to do about "blowing things up", "terrorism" or national "security". That's just the stuff we know so far, who knows what else it's being used for? Profiling? Preparing for the new totalitarian state where every citizen is kept "safe" by draconian legislation? Blackmail of political activists to get them to gather evidence or testify against their friends?
The argument "if you have nothing to hide you have nothing to fear" is the worst, most idiotic argument ever because of the incredible amount of na´vety and short-sightedness exhibited by the kind of people who make it.
Firstly, even if we assume that you could currently trust the NSA not to do anything shady with your information (which is dubious, considering the absolute lack of transparency and oversight, and all the times they've been caught telling outright lies to the public), the mere fact that they collect your data and catalogue it somewhere should be enough to alarm you. Even if you could trust the current NSA, the current CIA and the current government of the USoA, what guarantee do you have that x years down the line a new, "improved" Patriot Act won't be enacted and a future government won't decide to misuse this information in a way that makes your life intolerable?
Secondly, we already know NSA can't be trusted. We know the US government can't be trusted. By extension, Microsoft, Google, Apple or Facebook can't be trusted. I will treat every US-based service or company as potentially malicious in nature until this thing is sorted out and we get real transparency and real safeguards against abuse and privacy violations. For starters, the entire NSA needs to be disbanded, and any legislation that allows them so much leeway that they can freely spy and violate the privacy of everyone in the world needs to be changed.
It's a fact of life, that power corrupts, and absolute power corrupts absolutely. Whenever there is power that is unbalanced by proper safeguards, transparency and other checks and balances, that power will inevitably be abused for the benefit of those in power, and the ones who suffer are inevitably those with the least influence, the least resources to defend themselves.
Thirdly, speaking of "nothing to hide" - that's a terribly privileged assumption to make. You're speaking as (I assume, correct me if I'm wrong on any count) a middle-class, white, heterosexual male, living in a developed country - you are entirely unaware of the kind of problems people in less privileged positions face, why they would indeed have reason to hide things about themselves just so they can stay safe. A freethinker in China, a homosexual in Uganda, an atheist in Indonesia or Pakistan, a feminist in Saudi-Arabia... the list goes on, but you get the point. There are people who have to fear for their life because of their beliefs or ideologies, or simply because of who they are. It's incredibly arrogant to assume that everyone who isn't a criminal or terrorist should be ok with not hiding anything about themselves.