Elbows and boobs. Both are great in their own special ways, but they are definitely not the same thing. You and I might know that well enough, but it seems that Facebook has a little more trouble with the distinction. That's why they took down this elbowlicious picture.
The picture—which appears risque at a glance, but actually contains zero percent boob—was posted by Theories of the Deep Understand of Things with the specific goal of trolling Facebook's content filter. It's no accident that this kinda-sorta-maybe looks like boobs.
The picture was taken down fast, within 24 hours of posting. Theoretically, it was because the images violates Statement of Rights and Responsibilities, which prohibits posts containing "nudity" though presumably not that of bare elbows. Pictures of women breast-feeding however, have historically counted as nudity. TOTDUOT posted about the removal (with a censored version of the photo) on their Facebook page saying, noting that "FB moderators can't tell an elbow from a dangerous, filthy, uncanny and violent female breast."
Really it's just another case of a website erring on the side of "oh god take it down right now," which is becoming more and more common. And although they were wrong, you have to admit it kind of looks like boobs. Weird ones. For the first half-second. Maybe. [Theories of the Deep Understand of Things via The Daily Mail]