Faceborg crawls your posts, and even if your preferences say that you only share with friends, it adds links right back to your page from "community pages." So, when I posted the test post above on BP, it appeared on a BP community page, ignoring my privacy settings.
Here's another example:
Now, as the examples show, Faceborg's algorithms aren't very good. They searched my post for the string, "BP," and then friended my to a BP community page. And it all seems pretty innocuous, until you start imagining scenarios. For example, suppose a Rape Crisis Center has a community page, a woman posts on it, and a stalker who's monitoring that community page tracks the woman down through her Facebook page?
NOTE Of course, since Faceborg is free, you are the product. So it makes perfect sense, in my case, that Faceborg would want to sell my identity and commentary to British Petroleum, so they can send spam my way, or file a SLAPP suit, or whatever. Except, silly me, I thought sharing with "friends" meant just that, and not sharing what Faceborg laughingly calls "the community" (meaning by "community" the corporate persons to whom Faceborg sells our data for datamining and, presumably, actionable intelligence).