http://www.macworld.co.uk/mac/news/?newsid=3432561
Although may not be 100% true....
http://readwrite.com/2013/02/27/apple-isnt-censoring-your-dirty-emails
Apple's iCloud email service deletes all emails that contain the phrase "barely legal teen" it was revealed today.
Macworld has tested this by sending two test emails from a personal iCloud account. The message read "My friend's son is already allowed to drive his high-powered car. It's ridiculous. He's a barely legal teenage driver? What on earth is John thinking."
The second email amended the phrase "a barely legal" to "barely a legal". This second email was delivered fine, whereas the first is still undelivered. Upon further testing we discovered that the phrase is not blocked by Siri or iMessages, both of which can search and send messages containing the term: "barely legal teen".
Although may not be 100% true....
http://readwrite.com/2013/02/27/apple-isnt-censoring-your-dirty-emails