Apple's iCloud email service has a neat trick: instead of relegating emails that contains phrases like "barely legal teens" to your spam folder, it simply doesn't deliver your message. Macworld, which might have been tipped off by someone who would like to remain anonymous, has found that emails containing that phrase simply disappear:
Through our own rigorous testing, we've managed to confirm that emails containing the phrase "barely legal teen" are simply never delivered to iCloud inboxes. In fact, we found that even emails with the offending phrase contained in an attached PDF-even a zipped PDF-were blocked.
Even if you, like us, would almost never receive a legitimate email with such a phrase, this could still be problematic. For example, had you emailed someone about the fact that Apple blocks emails with the phrase "barely legal teens," that email would itself never arrive. And if, as with the person who originally reported the issue to Infoworld, you were attaching a work of fiction with such a phrase, that too would be blocked.
Even though its probably a mechanism to deal with the overwhelming spam that accompanies that phrase, it does seem like Apple is being a bit "prudish" by not even letting the recipient sort through their spam folder to find these "barely legal teens."
Besides, these teens are legal. But just barely.