A bit off-topic, but Facebook has always very intentionally been on the cutting edge of eroding privacy and frankly it doesn't really matter what you do. In 10 years people will care even less about privacy than they do now.
Due to Facebook people now-a-days are sharing significantly more than they would ever have been comfortable with even 10 years ago. That trend is only going to continue.
"one big database that was searchable and rampant for abuse by a rogue government agency"
I think this doomsday mentality is going to eventually disappear, and the socio-economical cost of NOT being on social media is going to grow. No advanced society (past a certain GDP) has slipped back into tyranny and all the people that think Obama is going to go fascist and read about how you love tranny porn are not grounded in reality.
Even if tomorrow the government had complete access to everyone's Facebook, life wouldn't change and the world would keep turning b/c ultimately the government doesn't have that much power. Even if Obama hated you personally the best he can do it get your balls fondled at the airport and maybe audit you (though if you pay your taxes, you shouldn't be concerned with that). And yeah, it's important to fight against tyranny and to for instance demand the dissolving of the TSA, but in reality the gov't doesn't care about you and as long as you aren't breaking any laws (and most people aren't) it's not really a big deal.