Free software leader Richard Stallman predictably advocates a boycott of Facebook: "...don't put your personal information in Facebook. If you use Facebook at all, just tell people how to contact you in other ways."
After another experiment with fairly intensive use of the network, I've dropped it again as a vehicle for personal sharing and removed the remaining data, leaving only a link to my Gravatar profile.
During my latest experiment I was mainly using it to share links from my news feeds and twitter stream. A few people picked up on these links, but really not enough to justify the bother of sharing them. In addition, a couple of times I received notification that content was blocked due to notification of it being "abusive or spammy". That's a very interesting message, about which I haven't been able to learn further from the web. Both of the postings blocked were "political" in nature: one was about the demolition and evacuation of a Bedouin village in the Negev; the other was about human rights abuses by Israel. Perhaps posting about abuse of Palestinian rights is considered "abusive" by Facebook or its readers. Or it could be that these messages result from the actions of personal friends on Facebook who lazily or irritably click the spam button, when a better choice would be to block a user's content. Anyway, the effect is the same, i.e. to discourage political conversation on this ostensibly "feel good" network of old and fake friends. Use of the service seems to be evolving. A couple of years ago, at least among my crowd, messages of protest and social change news were more prevalent and evoked more interest than now, and I did not encounter attempts to censor them. (Note: Jillian C York writes a lot about such issues in her blog.)
Facebook would define its strategy as attempting to provide us all with "the best possible user experience". In order to achieve this, it works on our news feed through various devious ways - some of which were described in a recent TNW article. However the effect is to create a network that feels like it's tightly and stiffly controlled. This makes Twitter's approach look ingeniously simple by comparison. Everyone can follow everyone. There's no need to ask anyone's permission. Anyone can post anything. Filtering is all left up to the user. While we wait for alternatives, Twitter is still so much better.
Update: Facebook new messaging service finally came to international users. I clicked through the introductory screen but opted out before being assigned a email@example.com address. I wouldn't want that, and don't know what it might expose me to. In addition, there are articles on the web about Facebook's censorship of certain content. Why should a network have the right to intervene with personal email? There's just too much about Facebook that is maddening.