"Even so, mankind will suffer badly from the disease of boredom, a disease spreading more widely each year and growing in intensity. This will have serious mental, emotional and sociological consequences, and I dare say that psychiatry will be far and away the most important medical specialty in 2014. The lucky few who can be involved in creative work of any sort will be the true elite of mankind, for they alone will do more than serve a machine."
You might enjoy Last Chance to See, from Douglas Adams.
It is a tells how he traveled searching for near extinct species. It is non-technical and non-fiction, but it is a Douglas Adams book, so he explains a lot of things and makes up stories a long the way. That is his style.
You have three groups, those who care strongly about seeing ${badstuff}, people who don't care enough to change the default, people who care strongly about not seeing the ${badstuff}.
By making it opt-out, you will get only those that feel strongly about seeing it. By making it opt-in, and following your query, you won't be able to separate those that really want to see it, from those that really don't care.
The group that doesn't care is big enough to make a difference.
Still, I have hope. Some people refuse to touch or even be near people who aren't clean. That forces others to be clean and propagates hygiene through society.
I wonder if we could do the same with information. Teaching little children that putting private information in public sites is dirty. The same way we teach them not to go around naked.
Maybe we should start using decentralized technologies? Go back to bittorrent, tor, irc. Teach everybody to encrypt, the same way we teach them to wash their hands. And for similar reasons.
I find the comparison suggesting, but otherwise useless.
All human endeavors have a political factor, but "political party" evokes something else. Many ads promise to make our lives better, yet they aren't call political.
This bit is spot on.