This forum gathers probably more technologically savvy and powerful people than any other public forum. And we're mostly social libertarian, worried about eroding digital rights.
Isn't it probable that this forum is a prime target for Big Brother to create detailed profiles of us based on our posts?
But I think most people overestimate how interesting they are. Hacker News is one forum on the Internet among literally millions. There are millions of other people who are also social libertarians, and millions of people worried about eroding digital rights. These characteristics do not make you interesting. Hell, digital rights in general are not that interesting to people in Washington - for the most part, our legislators vote the way that whichever lobbyist who last had their ear wants them to, and the American public just gets caught in the crossfire.
The folks that the NSA cares about are those that advocate violent overthrow of governments, or who are a credible threat to U.S. interests abroad. Hacker News readers, by and large, are not a credible threat; we talk, but few of us will get off our butts and do. And so we're just not important enough for the NSA to care.