You've created publicly accessible aggregations of members expressing interest in a potentially limitless set of categories (whatever you may choose to call them). You've taken previously private profile information and pre-emptively linked it to these public categories. Even where some of this information was previously publicly visible, it wasn't so conveniently publicly indexed; someone would have to visit individual profiles in order to turn it up.
By the way, religious and political views do not only express themselves in the fields you mention. What disrespectful soul there decided to take my "Favorite Quotes", with access previously restricted to "Only Friends", and plaster them -- without so much as a warning -- all over my public profile?
I've been pretty cautious, and there was nothing very incendiary or damaging in them, but it still caught me out.
For me, it was the last straw. I hope FB, or at least its current Management and, ahem, "policies", follows MySpace into a death spiral, taking their accumulated financial equity with them before they have a chance to cash out.
I hope HN will pardon a bit of unusual vehemence from me, but Facebook has come to be, simply stated, slimy. I guess I write this comment in the vague hope some fraction of the message might get through whatever reality distortion field they're currently running in-house.
Finally, as a few commentors have started to point out, as Facebook continues to publicize their members' data, those members more and more tightly control their expression. The result is that the site continues to become blander and blander, less and less "personal". There's only so long people will continue to find novelty and interest in generic updates.
Control over privacy. Personal expression. What brand-building feature are you going to kill off, next?
I remember when "everyone" was on AIM. Even if you preferred another platform, you used AIM because that's where the bulk of the general (U.S.) population was, for IM; they'd "won" the IM platform war. I don't think I've even signed on to the thing in a year or more.
A lesson for any "winner".
P.S. As for fanning being public, it used to be someone would have to seek your ID out on those different fan pages. Then, around the end of the year, Facebook decided to (pre-emptively, again) display that information in aggregate for each user on their public profile. Maybe googling might have exposed some or all of it previously, but you sure made it a lot more convenient. (E.g. for that HR staffer looking for a quick means to winnow a stack of resumes.) And I'm not even addressing the publication of everyone's friends, etc.
If you've read this far, thanks for taking the time to consider my response. It's not meant to be personal. (Well, except against those setting these policies at Facebook. Even then, it's the policies that elicit the response; the people I don't know personally.) It's strongly phrased to emphasize the points, and the frustration they cause.