Facebook has proven repeatedly over the past few years that they're not at ALL interested in preserving your privacy.  But apparently they're REALLY vigilant about preserving your modesty.  So they've got that going for them.  Facebook recently pulled a photo of a woman in a bathtub, because her elbow REALLY looks like an EXPOSED BREAST. 

The angle of her arm makes it look like it's part of her chest, and the pinkness of her elbow makes it look like a nipple.  Within 24 hours of posting the photo, Facebook moderators spotted it and removed it under their "indecent material" policy.  But here's what probably happened:  Their filtering software constantly monitors uploaded photos and tries to spot nudity.  If it flagged the photo and a moderator looked at a small thumbnail, they really would think it was a breast.  So it was yanked. 

(Gawker)